Page 2 of 3 < 1 2 3 >
Topic Options
Rate This Topic
#92299 - 08/06/17 01:37 PM Re: Chevy 250 hp confusion [Re: Tracker64]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: Tracker64


I really need to upgrade to and Hei like you did. Everyone seems to do that./ I have new points, and complete tune up. Actually runs very smooth, for except a very slight rough idle in gear, and that fluttering once in a while, when under throttle demand.

Yours looks nice. I need to get some photos of mine. I do have the 4 blade fan. I didn't know if going to the three blade or electric would do much. I see a lot are doing it though.

my stock air cleaner was missing the lid. So I put a open air filter on. One of those Mr. gasket chrome ones from summit. I dunno if that hurt anything doing that. As in....changing the way the carb acts?
Although when I got the car, it was worse. I got it top run better. Just started to do the fluttering recently while under acceleration.


Yeah, for street performance the HEI is pretty good from the factory. Factory coil is all that is needed.

Yeah, all the car 250 inline sixes came with the fixed 4-blade fan from the factory until they discontinued them after 1979. The truck motors came with the same fixed 4-blade fan but had a larger diameter water pump pulley it was mounted to reduce the drag of the accessories. When they went to a 3-blade clutch fan for trucks (I don't remember which year) they used the smaller pulley from the cars. The least parasitic drag combo would be the early truck pulley with electric fans, next best would be the truck pulley and clutch fan. I haven't been able to find an early inline truck pulley, with grooves in the right spot yet for PS and alternator. When I switched from fixed fan to electric fans for a short while, I saw a jump of almost 3mpg in fuel efficiency.....so yeah big difference. I switched to the clutch fan temporarily while I sorted out the electrical issues as I couldn't find a switched wire for the regulator, and just had it wired to the battery and always on but that was too hard on the battery.

Open element air cleaner flows better, but it's sucking hot engine compartment air, so it's mixed bag. My factory THERMAC air cleaner actually has a hose that draws cooler air from in front of the radiator support. But it is right behind the left turn signal. So I removed the assembly, created a duct with reflective inside and a cut out for the turn signal housing, and now i have a stealth ram air duct. The flexible 3" duct I got to replace the factory paper one also allows a pretty direct feed of the ducted air to the air cleaner. My air cleaner probably doesn't flow as well as your open element, but with my K&N filter and cool ram air ducted to it, it's probably probably a tie between the two as far as power and fuel efficiency goes.

I'm just wondering if you capped the vacuum port that feeds the factory air cleaner? The vacuum that actuates the flap in the snorkel is the full manifold port on the bottom of the Monojet. It has a metal Y port with one angled up to supply vacuum to the THERMAC, and one pointing straight out that the distributor vacuum advance is attached to. Did you cap it off or just break the second port off and push the vac adv hose all the way onto it?

Yeah cleaning up the rust and grime is lot of work. You have to get in there with degreaser, toothbrushes, rags, and elbow grease. Sand and rustoleum the rusty parts. It's best to remove as many parts as possible to clean and really get in there. Plus when they are off, it is easier to repaint them. The gold cadmium parts are best replaced or just painted with cast pant. The aluminum and unpainted metal can be clear coated once the oxidation and rust is removed, or painted with aluminum paint and cast iron paint. I use the cast-blast paint for the hinges and other items that have that phosphate coating. Rattle can Chevy engine orange is ok for the engine, but the parts that are close to the exhaust manifold will definitely burn off after awhile. It's best to remove the valve cover, engine lift eyelets, side covers, water neck, even water pump to clean paint those separately. The rest is removing hoses, belts, and wires; or moving and masking them, and spraying as much of the engine as you can reach. When you go to remove head and intake, it's better to paint those with a spray gun and proper engine paint so that they last. That's what I plan to do as the only way to get the GM corporate blue is the canned paint, they actually put Chrysler blue in the rattle cans and label it GM blue.......there's definitely a difference.


Edited by Lifeguard (08/06/17 01:41 PM)

Top
#92300 - 08/06/17 03:40 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
I'm going to definitely do an HEI swap soon. I do see a lot of not mostly all have done that.

For the fan I'm thinking electric as long as I can find one that bolts up. I'm sure some fabricating will be involved. The wiring....that's where I'll get lost. On where to wire it up and how to make it come on a a specified temperature.

My vac ports are all hooked up. Odd thing is...when I removed the factory air cleaner. It had a small vac line on it, but nowhere for it to go. Quite odd.
I agree I'm pulling more air with the aftermarket, unfortunately hot air. Ugh

I'll be on my laptop in a few hours.

I found a brand new rebuilt carb still in the box from classic industries on the Craigslist I can grab for about 80.00.

He took photos of all four sides for me. So I took photos of all 4 sides of mine. I have to upload them and post them here. It's for a 69, and mines a 74.

It's missing one vac port that goes to my charcoal canister. I don't think that's important? And the throttle linkage looks a little different, at least to me. Maybe it can still be used.

I'll upload both carbs of all 4 sides and maybe you can tell me if it would work?

Top
#92302 - 08/06/17 05:40 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Okay here we go!! LOL

If this carb can be made to fit, then I may grab it for 80 bucks, its never been mounted.

It looks different to me at the throttle linkage, and also there is no place for a choke pull off. So I don't know how my choke would work. This is for a 69. Mine is a ...74.

His is missing the top vac port. On mine it only goes to the charcoal canister. SO maybe thats not a big deal?

The bottom port on his is like mine, goes to vac advance. Hopefully on his, its the same "type" of portto make the vac advance work properly...

Here's His...



Here's mine....



His...Looks the same there, same vac port..



Mine....



His.....



Mine...



Okay....Now one more confusion...His throttle linkage looks different for a 69. And my return spring is set different.... I dunno??



Mine.....






Here's the box with the part number. I dunno if that helps..



.


Edited by Tracker64 (08/06/17 06:15 PM)

Top
#92304 - 08/06/17 06:11 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Just a photo of my engine for reference....


Top
#92308 - 08/08/17 12:05 AM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Alright, I can see your kick down linkage for your auto. And is see that there is no AC and no power brakes just like mine. Nice valve cover there. wink I'll put up some HEI and electric fan pics later.

For the carbs, your factory carb looks similar to mine, but there are some odd differences. I can't see where the lines for the EGR and EVAP (charcoal) canister are going or coming from. Could you get a pic of the front of the engine and over the EVAP canister so I can figure out how your hoses are running? Alright I got a few more pics of my carb:



First here's a pic of my air cleaner and a lot of other things off so you can see how everything routes. I have the factory assembly manual, so I have checked all the attachments to make sure they are correct. I'm putting it on top so it is right below your engine pic in the message above so you can see them both.



I don't have pic of the front of my carb, but here is the passenger side of it. You can see the solenoid is there like yours, but I have an electric choke there and you have a hose going somewhere? You also have what I guess is the timed vacuum port on this side, which should be running to both the EGR and EVAP (charcoal) canister? It's hard to see, but it looks like you have the main EVAP hose and PCV hose running to a vacuum port on the manifold in the same place as mine.



Here's the rear of my carb. Aside from the lack of an electric choke on yours, it looks the same to me. The EFE vacuum line appears to connect to a port at the base of your Monojet, while on mine there is a vacuum port on the manifold for it.



Ok, here is a shot of the driver side of my carb. Right away on the upper top right you see a port that is not on yours. This is a timed vacuum port and it runs to a thermal valve on the water neck which then runs to the EGR and EVAP. On the upper left side is a hose on mine that vents the fuel bowl to the EVAP to prevent fuel vapor in the bowl from being released to the atmosphere. On your's someone has capped it.....which there really is no reason to as this just passively collects fuel vapor from the carb when parked and keeps it from smelling up your garage. The Holly 390cfm has bowl vents that just vent straight up so this hose is useless once you switch (although you could drill a hole in the bottom of the air cleaner and get a port to seal it too and hook the hose to try to collect any vapor settling on the bottom of the air cleaner).

On the top of the pic you see the bottom of my air cleaner and the hose running from there to full vacuum port at the base of the carb in a tee fitting with the vac adv line too. I suspect this is where your dangling air cleaner vac line plugged in too, but someone broke that part of the tee off and pushed the vac adv hose all the way on to cover the hole. Pull it off and see if there is a broken off port tee there.



Here is a labeled pic of how the hoses function. It's hard to see the lines running from the PCV and EVAP to the manifold port which has a tee fitting as well.



And here is the 1978 49-state diagram of how everything runs. I made notes on for a Holley-390/Offy/Stovebolt swap as to which hoses can be retain and what they will plug into, and which need to be deleted.



Here's my labels where the hoses go on the Holley 390cfm for the swap.



Here's one more shot to show how the '78 is set up. You can see two thermal valves screwed into the water neck. One on top is attached to a delay valve in the line running from the distributor vacuum advance to the full vacuum port on the bottom of the Monojet.

The second one is on the bottom half of the neck and has one line running from it to the vacuum source on the carb which is the top timed vacuum port. The other line runs a few inches and then has a red plastic Y to split the line with one going to the EGR. The other line goes to the EVAP canister where there it plugs into one of the two valves on top of it (I forget which one, need to snap a pic of that).

I hope that helps. Take some pics of the front of your engine and the EVAP (charcoal) canister and I can see how your hoses are routed, because they are not quite the same as mine.


Edited by Lifeguard (08/08/17 12:11 AM)

Top
#92311 - 08/08/17 06:52 PM Re: Chevy 250 hp confusion [Re: Lifeguard]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Okay I gave it my best! LOL I only got to remove the valve cover so far. I haven't had the car long. I hope these photos help. I labeled them the best I could.

The prior owner had a rebuilt carb put on, but probably quite a while ago. He seemed to understand cars, but I wouldn't call him a mechanic. So if he messed up the vac lines, I wouldn't be surprised.












Top
#92312 - 08/08/17 08:48 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
I'm going to have to study your hose layout more, but here's a few quick observational differences I see.

The EVAP (charcoal) canister is different from mine. It is like a V8 canister and not the L6. maybe they changed, or maybe the carb or canister are not original. The V8 only has one vac valve on top because the second one is built into the 2GC or Qjet bowl. The Monojet just has the single port above the bowl that leads to the second vac vent on the EVAP canister.

It looks like the full manifold vacuum port on the driver side, which is the vac-adv/THERMAC on mine, is the EGR port on yours. My EGR is run off a timed port on top. This must have been a change later, maybe when the catalytic converter was introduced. The thermal valve for your EGR is located on top of the water neck, which is where the thermal valve is for my distributor vac adv.

I see your distributor vacuum advance just goes straight to the advance canister without a delay valve or a thermal valve on it. It's on the bottom so this should be a a full manifold vacuum port too.

I forgot about the Th350 vacuum line. Too used to a manual now.

Yeah, the port on the manifold sucks fuel vapor from the crankcase through the PCV and fuel vapor from the EVAP (charcoal) canister to mix with the income air/fuel mixture.

There's a lot of electrical tape on the wires above the intake. Looks like someone pulled the plastic wire housing off them and just taped them up afterwards.

Notice the hose coming off the EVAP (charcoal) canister and running over the inner fender and disappearing beside the firewall? That's the line to the fuel tank. When I got my Camaro it was there but disconnected from the metal line. Stunk up the garage with gas vapor like you can't believe. The EVAP (charcoal) is worth keeping just for this reason alone. Plus it saves gas instead of venting it to the atmosphere......gas you paid for, why would someone do that? :P

I'm still wondering about the lack of an electric choke on your Monojet? Was there a heated coil choke on the Monojets earlier like the 2GC? I don't see where it is housed if there is one?

Top
#92313 - 08/08/17 09:07 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
BTW, to delete your EGR, you just need to cap the vacuum port on the carb. You can just pull the hoses then, as the valve stays shut without vacuum and no exhaust enters the intake. You could take the thermal valve off the water neck and just put a plug in it too. If you want to go far enough, you can make a plate to cover the opening after removing the EGR valve. But once you throw the Offy and Holley 390cfm on it, there is no place on the Offy for the EGR anyway.

BTW, just noticed the blue color of the Nova, I like that color.

Top
#92314 - 08/08/17 10:57 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Thank you its the factory midnight blue.

He did replace the carb sometime ago. So who knows when you buy a rebuilt what your really getting.

My EGR goes to that switch on the thermostat housing. My buddy did tell me to unplug the EGR and cap that hose off. He said I would notice a slight difference.

I'll chase that canister hose and see where it goes. I just assumed it went back to the gas tank. I'll see where its going. I do smell gas once in a while right after turning off the car walking past it in the garage. But I have no leaks anywhere.

The prior owner replaced the head gasket with the guidance of a buddy. So who knows if they have some of the hoses hooked up wrong. Very possible just from talking to him.

I checked the numbers on the carb and its for a 1976 chevy C10 manual truck. However...I cant go by that with a rebuilt. They just throw parts together from a bunch of carbs.

Theres a spring heated coil the has an arm that leads up to my choke from the manifold. But I don't believe that or the choke pull off is working. I have no electric choke.

Thats why I was considering that carb that I showed photos of previously on this thread. But...the throttle arm linkage looks different I showed it on my post.if you scroll back youll see what I mean.

Should my hose coming from the vac advance have constant vacuum or only under throttle? I can test that tomorrow.


Edited by Tracker64 (08/08/17 11:05 PM)

Top
#92315 - 08/09/17 12:47 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Yeah, it makes sense that maybe the carb was a later carb and the EVAP (charcoal) canister is the original. And that the electric choke was removed and the fuel bowl vent was capped.

Yeah, my hose was pulled off the metal line to the tank right under the hood hinge. The first emissions they controlled was the fuel vapor that escapes into the atmosphere and stinks up garages. The fuel tank first the vent in the cap changed to a one way vent, then it was unvented and the EVAP canister added to capture the fuel vapors. The carbs were also vented to the EVAP at some point, but from yours it looks like maybe that happened later. And of course the blow-by vapor in the crankcase which the PCV valve was added to close up the crankcase so it didn't vent to atmosphere.

So you have three places you might smell fuel vapor from. The carb which now has an open element air cleaner, so fuel vapor in the bowl just leaks out there. The valve cover breather which used to attach to the air cleaner so vapor would go there (probably not much when engine is off). And of course the line from the fuel tank to the EVAP (charcoal) canister.

I'm still trying to find a diagram for your hose layout online. I found another one for my year which is a pretty good one showing how the top of the EVAP canister looks different, and the THERMAC line attaching in the same spot as the vacuum advance line (front of engine is to the left, driver side is bottom).



Oh, he had the head off too? Probably used the standard rebuilder gasket with 0.040" thickness, which means your CR was reduced. Aside from the radiator swap and the factory carb rebuilt, my Camaro was completely unmolested. Although they had switched the vacuum hoses for the EGR/EVAP and THERMAC around, and switched the #3 and #4 spark plug wires. But I caught those goofs before I really got it running again. Good to have the factory assembly manual.

Ah ok, that heated spring in the manifold sounds like a similar setup as what they did for the 2bbl V8 with the 2GC carbs. That's why it wouldn't need the electric choke. My guess is that the difference between your layout and mine occurred in 1975 when they introduced the catalytic converter and the integrated cylinder head (intake and cylinder head combined into one casting). But 1974 may have had some of the changes due to the HEI as well. I gotta find some diagrams to see when they changed what. I find the running changes really interesting.

GM only use full manifold vacuum for their HEI. I'm not sure if the placement of your points vacuum line is full/manifold or ported/timed vacuum. It's a little higher on the carb body, while the EGR port is low on the throttle body base. The spot where your EGR is plugged in is where my vacuum advance and THERMAC hoses are plugged in. So maybe you should repurpose that port for your HEI when you swap to make sure you have full vacuum. But mine also has a distributor TVS (thermal vacuum switch) with a delay valve attached as well.

Two things I am not seeing on your engine are the EFE system and the heat stove on the exhaust manifold? Does your's have the EFE flapper valve on the exhaust manifold that redirects exhaust to the bottom of the intake manifold during warmup? There should be a vacuum canister that actuates it and a vacuum port for it on the manifold? Maybe this was a later edition too, and the intake heating was just passive on yours? There should also be a metal shroud attached to the exhaust manifold with a round fitting that a rigid metal tube attached to and then ran up underneath the snorkel of your air cleaner? The flapper valve in the snorkel has a vacuum hose that runs to a vacuum switch in the underside of the THERMAC air cleaner and then a second hose to a vacuum port on the carb? You said you had a mystery hose on your air cleaner, so I assumed it was to the THERMAC flapper valve in the snorkel? Unless maybe you were talking about the hose that runs to the breather filter in the side of housing that used to connect where your valve cover breather is now? Take a pic of your air cleaner and I can tell you which hose it is.


Edited by Lifeguard (08/09/17 12:49 PM)

Top
#92316 - 08/09/17 03:05 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
I'll respond to your post longer a little later I'm actually in the garage using my phone. So it makes it hard for me to respond to all the comments.
M
That guy just texted me and told me I could have that brand new carburetor for 50 bucks. The one that I have in my previous posts with the photos. I showed a comparison of all four sides of both of our carburetors in the post.

It's really tempting I could probably figure out the throttle linkage. But I realized one thing.

There's no port on the base plate for my automatic transmission modulator valve. I don't know if there's a way around that. If you scroll back you'll see the photos of the carburetor he has.


Edited by Tracker64 (08/09/17 03:06 PM)

Top
#92317 - 08/09/17 03:40 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
There's really kind of a hole in diagrams for hose layouts in the mid '70s, specifically '74 and '75 are completely absent.

The only diagram I can find for 1973 is this one for the Vapor Control (EVAP or charcoal canister):


here's a 1976 diagram of the EFE route (this is identical to my 1978 layout), but I can't find a diagram of the rest of the lines:


The 1977 diagram is interesting, as it looks like the layout of your 1973 EVAP remained unchanged through '77. The EFE is there, and the advance is similar to your layout:


The 1978 and 1979 diagram are identical to this one I posted earlier. My year seems to be the one with the most changes. The vacuum advance was given a TVS and delay valve and the EVAP got a vent from the fuel bowl with it's own valve.


Here's my EVAP canister for 1978 and 1979. Please excuse the dust and dirt, it's been sitting for a year now while I get back to finishing all the fluid changes, coolant upgrade , and fixing the exhaust. You can see they added an extra vacuum valve on it that the fuel bowl vents to. The line to the fuel tank is between them:


And then here is that fuel line running under the hood hinge where someone had disconnected it, making my garage smell like a fuel can:


And I snapped a couple shots of my THERMAC air cleaner with the vacuum hoses attached:



I looked behind my electric choke and there is no hose where there is one for your choke. Where your vac adv and the EVAP (charcoal) line plug in there are two holes in the body of the carb but no ports. Must be internally plugged.


Here's the tee port on my base throttle body with the hose to the THERMAC off, and the hose to my vac adv (through the TVS and delay valve along the way) attached. On your's the EGR is plugged in here:


I also got a shot of the front of my carb while I was at it:
[img]http://i.imgur.com/CzRPkCg.jpg[/img]


Edited by Lifeguard (08/09/17 03:48 PM)

Top
#92318 - 08/09/17 05:34 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Thank you so much I'm leaving work right now as soon as I get home Ill get on my laptop so I can see the photos better.
Let me know what you think of my post above yours with that carburetor situation. I don't know whether to purchase it or not.

Top
#92319 - 08/10/17 10:10 AM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Okay I'm going to study your vac line diagrams. Thank you so much. That will help me a lot.
I am off today so I went into the garage. I don't think I have a carb issue. Although I do want to go over them vacuum lines according to your chart.

I have an intake gasket leaking. I know the prior owner had tried to replace it, and I think he screwed up.
When I got the car it was leaking there and I snugged it up and it stopped leaking, but now the leak is back.

I have a new intake gasket and exhaust gasket set by Fel-Pro on hand. Never change them before it looks like a lot of juggling.

There's a YouTube clip I made from my phone I don't know how well you'll be able to hear it starts stumbling when I hit it with carb spray there. It's towards the back near the firewall. I did the best I could with the video so I don't know if you'll be able to tell or not. But soon as I spray that area the whole motor start shaking and Idle drops down lower. Here's the clip.

https://youtu.be/BH2p184jmV8


.



.




Edited by Tracker64 (08/10/17 05:10 PM)

Top
#92320 - 08/10/17 09:53 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Sounds like a reasonable diagnosis. Yeah, keep the bolts and hold downs sorted to which holes they go to, they are not all the same and have a specific order.

I wasn't sure what you need the new carb for, there wasn't a lot on it as far as enough vacuum ports for everything and and the missing choke linkage and vacuum can that you would have to transfer over? And you said your solenoid was not working, so if that is still the case then you would need a new one with either your current carb or the new one?

BTW, I think after looking at my carb, yours, and the diagrams I have the passenger side vacuum ports figured out. Starting with the choke vacuum, your can draws from a port that is behind my electric choke, so my can actually draws from another port closer to it. I assume this is a timed vacuum port due to how high up on the carb it is. My carb has two plugged holes below the electric choke, while your's has the EVAP (charcoal) plugged into the top one and the distributor vac adv into the bottom one. On mine and in the '77 diagram the EVAP is located high on the other side and is timed vacuum, while the advance is coming off the low full port that your EGR uses. So my guess is despite how close those two ports on yours is, the upper one is timed for the EVAP and the lower full for the vac adv. Inside, they are drawing vacuum from opposite ends of the carb. For some reason in '73 the EGR was full manifold vacuum, and by '77 at the latest it was timed vacuum. BTW, do you have the EFE flapper valve on the exhaust manifold?

Turn your phone sideways to widescreen so the viewer can see everything, I like to ogle while I listen. wink I think I hear the change when you spray it. The intake sealing was a common problem on inline Chevys, that's why they went to an integrated head and intake from '75 to '78. But then they had head cracking issues and put the non-integrated top end back on for '79.

I did the exhaust on mine for IntegratedJ because he wanted to know what the Z28 exhaust sounded like on it. I did some under hood video but I guess I didn't upload that:

https://www.youtube.com/watch?v=cxzW7miIM6s
https://www.youtube.com/watch?v=yMySPecpiJA

I really want to do a tuning how-to video for the inline six when I'm done organizing the garage and got it back together again.

Top
#92321 - 08/11/17 08:25 AM Re: Chevy 250 hp confusion [Re: TonyPa]
gbauer Offline
Active BB Member

Registered: 08/11/14
Posts: 810
Loc: Maryland
If you're going to change the gasket use some high temp copper RTV on it. You'll get a much better seal.



When you do it clean both sides of the flanges, smear it on both sides of the gasket, give it 15 minutes, put it on, put on the headers and intake, snug everything but don't torque it down yet, then wait until the next morning to torque down the nuts on your studs. This will ensure a good seal.

I had a heck of a time getting mine to seal until I heeded the advice of my elders here and used the RTV.


Edited by gbauer (08/11/17 08:26 AM)

Top
#92322 - 08/11/17 10:31 PM Re: Chevy 250 hp confusion [Re: gbauer]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: gbauer
If you're going to change the gasket use some high temp copper RTV on it. You'll get a much better seal.

When you do it clean both sides of the flanges, smear it on both sides of the gasket, give it 15 minutes, put it on, put on the headers and intake, snug everything but don't torque it down yet, then wait until the next morning to torque down the nuts on your studs. This will ensure a good seal.

I had a heck of a time getting mine to seal until I heeded the advice of my elders here and used the RTV.


Good tip. No leaks on my integrated exhaust manifold, so i don't need it until I swap the whole top end at once. All at once kind of thing.

Top
#92325 - 08/13/17 09:42 PM Re: Chevy 250 hp confusion [Re: Lifeguard]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: Lifeguard
Sounds like a reasonable diagnosis. Yeah, keep the bolts and hold downs sorted to which holes they go to, they are not all the same and have a specific order.

Sorry for the delay. I got stuck working 16 hour shifts, because people are lazy and call off work! Ugh!!!

Anyhow! I am wondering when this guy and his buddy did the head gasket, if they mixed them up. I noticed the one nut towards the front of the engine doesn't have much thread.."stud" sticking out of it.


I wasn't sure what you need the new carb for, there wasn't a lot on it as far as enough vacuum ports for everything and and the missing choke linkage and vacuum can that you would have to transfer over? And you said your solenoid was not working, so if that is still the case then you would need a new one with either your current carb or the new one?

I did decide against his carb. If I have to, I may rebuild mine. I see that Mikes carb parts, sells the kits. And even a new float. No solenoid for mine though. I can't find one anywhere.
They all look odd.
My carb that is on there, the numbers come back to a 76 Chevy C10 though, with manual tranny. But I also can't go by that. They seem to just slap a bunch of "mixed bag" parts together sometimes when their rebuilding carbs on a assembly line.


BTW, I think after looking at my carb, yours, and the diagrams I have the passenger side vacuum ports figured out. Starting with the choke vacuum, your can draws from a port that is behind my electric choke, so my can actually draws from another port closer to it. I assume this is a timed vacuum port due to how high up on the carb it is. My carb has two plugged holes below the electric choke, while your's has the EVAP (charcoal) plugged into the top one and the distributor vac adv into the bottom one. On mine and in the '77 diagram the EVAP is located high on the other side and is timed vacuum, while the advance is coming off the low full port that your EGR uses. So my guess is despite how close those two ports on yours is, the upper one is timed for the EVAP and the lower full for the vac adv. Inside, they are drawing vacuum from opposite ends of the carb. For some reason in '73 the EGR was full manifold vacuum, and by '77 at the latest it was timed vacuum. BTW, do you have the EFE flapper valve on the exhaust manifold?

I'll have to see if theres a flapper valve. But I never noticed one. I have that little shell with the hole for the pipe that goes up to the air cleaner. Kinda like from the exhaust, to heat the carb I am guessing. I disconnected my EGR, and plugged that port on the switch on the Thermostat housing. they sure did a lot of moving around with the vac lines over the years.


Turn your phone sideways to widescreen so the viewer can see everything, I like to ogle while I listen. wink I think I hear the change when you spray it. The intake sealing was a common problem on inline Chevys, that's why they went to an integrated head and intake from '75 to '78. But then they had head cracking issues and put the non-integrated top end back on for '79.

I'll take a video and kind of move around the whole engine tomorrow. I'm off tomorrow. I'll rev it up...etc. I need some vac caps. I plugged a few hoses, and it helped a bit. I snugged the intake down again!! Unreal! Anyhow, I will get the new gasket on soon. I was going to actually take a extra day, and wire wheel it, and paint it while its off. I never did one on these motors, so hopefully I don't need a second set of hands while installing the gasket.

I did the exhaust on mine for IntegratedJ because he wanted to know what the Z28 exhaust sounded like on it. I did some under hood video but I guess I didn't upload that:

https://www.youtube.com/watch?v=cxzW7miIM6s
https://www.youtube.com/watch?v=yMySPecpiJA

Thats sounds nice!! I want mine to sound like that. Is that langdon headers, or?? And what kind of mufflers. I can't believe how good that sounds!!

That would be great, I would be watching that!!

I really want to do a tuning how-to video for the inline six when I'm done organizing the garage and got it back together again.


Edited by Tracker64 (08/13/17 09:42 PM)

Top
#92326 - 08/13/17 09:45 PM Re: Chevy 250 hp confusion [Re: gbauer]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: gbauer
If you're going to change the gasket use some high temp copper RTV on it. You'll get a much better seal.



When you do it clean both sides of the flanges, smear it on both sides of the gasket, give it 15 minutes, put it on, put on the headers and intake, snug everything but don't torque it down yet, then wait until the next morning to torque down the nuts on your studs. This will ensure a good seal.

I had a heck of a time getting mine to seal until I heeded the advice of my elders here and used the RTV.


I have never tried that! I did see someone using that on a car show I was watching. I think it was the spray on copper. I am not big on spray stuff though. I would rather smear it on by hand.
I am glad you added this. And I appreciate you explaining the way to use it. I would have put it on and just torqued it down.
I need to find the tightening sequence and torque for it. I will remember now to do it the way you described. Thank you!

Top
#92327 - 08/14/17 01:42 AM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Yeah, easy to get distracted. My project is on delay until I get the garage squared away for access, and that's only after I get done with yard work, fencing, and back deck.

Yeah, it is pretty easy toe mix the bolts up on the manifolds. I'll try to find my notes on which ones are which lengths and torquing order.

Hmmmm.....'76. I don't have a diagram for that on the EVAP, but the '77 doesn't show a float bowl vent. But yours has one? Maybe mix and match parts. Looks like the top with the float bowl vent was a '78 and later addition.

Yeah, the little shell on the exhaust manifold is to warm the air for the stove pipe going to the THERMAC air cleaner. So sounds like the air cleaner in '73 was the same as '78/'79 at the end of the car run.

You can cap the EGR line right at the carb. The TVS on the water neck just has a valve in it that opens when the engine is hot enough. It won't hurt anything to leave the ports open, and you can just remove it and put a plug in there later. My TVS for the EGR is actually on the side of the lower water neck, and the top hole has a TVS with delay valve for the dist vac adv.

'73 may have been too early for the EFE flapper exhaust manifold.

Yeah if you got it off, you might as well make it look pretty.

Thanks, but my exhaust is still the factory exhaust manifold attached to the 2nd version integrated cylinder head/intake. In '75 when they put the catalytic converter and integrated head on, they increased the exhaust manifold and header pipe to 2.25" and routed under the engine to the passenger's side to run back to the cat. The guy before me cut everything from the catalytic converter on back off. So I just have a 2.25" to 2.5" piece on the end going to a 2.5" pipe in place of the cat. Then from there on back it is the '77 to '81 Z28 cat-back exhaust. A 2.5" flange splitting into a Y of dual 2" pipes to dual resonators. The resonators exit through dual 2.25" tailpipes. Except for the two resonators, it is just open pipe. It's still identifiable as a six since all the cylinders empty through one header pipe. But when you put a dual exhaust with headers and no crossover, you get a different sound of rap-rap from the inline. A crossover will make it sound more like mine. Whichever is to your taste.

Yup yet another project. But once I get everything changed and running again, I could just film my tuning.

Top
#92357 - 08/17/17 05:12 AM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Finally found my notes on the intake and exhaust bolt pattern:


Top
#92358 - 08/17/17 06:47 AM Re: Chevy 250 hp confusion [Re: Lifeguard]
stock49 Online   content

Active BB Member
****

Registered: 04/09/03
Posts: 999
Loc: Medina, Ohio USA
It's a good thing to have three carbs blocking the view :-)

Top
#92368 - 08/17/17 12:46 PM Re: Chevy 250 hp confusion [Re: stock49]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: stock49
It's a good thing to have three carbs blocking the view :-)


Yeah, I don't remember who posted that. Obviously someone with a tri-manifold. But that should help sort his retainers out.

Top
#92382 - 08/21/17 06:42 PM Re: Chevy 250 hp confusion [Re: TonyPa]
preacher-no choir Offline
Active BB Member
****

Registered: 01/26/10
Posts: 485
Loc: left out
3.08 gears are the "kiss of death" for these sixes, a very good rear gear ratio is a 3.55--very well rounded ratio--it will wake up the smallish motor and let it run more freely--if you do this first it may save you a lot of motor hop-up spending--it's really a wake-up move. The original '62 Chevy lls were equipped with 3.55s, then in '63 they switched to 3.08s and performance plummeted. I had a '63, and the '62s would embarrass me. Switched to a 3.55 and wow what a difference--almost like going from a two-speed PowerGlide (1,82 low gear) to a three speed Turbo hydramatic (2.54 low gear)when you hit the "go" pedal---OOOOPS--I see now I came 'waaay too late with my suggestion!!


Edited by preacher-no choir (08/21/17 06:51 PM)

Top
#92383 - 08/21/17 10:02 PM Re: Chevy 250 hp confusion [Re: preacher-no choir]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: preacher-no choir
3.08 gears are the "kiss of death" for these sixes, a very good rear gear ratio is a 3.55--very well rounded ratio--it will wake up the smallish motor and let it run more freely--if you do this first it may save you a lot of motor hop-up spending--it's really a wake-up move. The original '62 Chevy lls were equipped with 3.55s, then in '63 they switched to 3.08s and performance plummeted. I had a '63, and the '62s would embarrass me. Switched to a 3.55 and wow what a difference--almost like going from a two-speed PowerGlide (1,82 low gear) to a three speed Turbo hydramatic (2.54 low gear)when you hit the "go" pedal---OOOOPS--I see now I came 'waaay too late with my suggestion!!


I assume that is a recommendation for the auto equipped cars, or at least the 2.85:1 3spd through 1974. In 1975 to 1977 they had a 3.11 first gear, and then 1978 and 1979 had the 3.50 first gear. 3.55 is a bit deep for those wide ratio gear boxes.

Top
#92389 - 08/22/17 08:11 PM Re: Chevy 250 hp confusion [Re: Lifeguard]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: Lifeguard
Finally found my notes on the intake and exhaust bolt pattern:



Thank you! I appreciate that. I will try to see if he had them on wrong, I am quite sure he did. Some of the nuts are right at the edge of the threads.

I have been on my wifes Subaru, I think I am almost done, and can get back on the Nova. I keep starting it up an letting it run every 3 days. But I keep a battery tender on just in case. LOL

Top
#92390 - 08/22/17 08:13 PM Re: Chevy 250 hp confusion [Re: stock49]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: stock49
It's a good thing to have three carbs blocking the view :-)


Hahah...Theres a guy near me selling a offy intake with dual one barrels, but he wants 500 bucks! And basically the carbs are free, because their probably worn out. Thats kind of a high price

Top
#92391 - 08/22/17 08:17 PM Re: Chevy 250 hp confusion [Re: preacher-no choir]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: preacher-no choir
3.08 gears are the "kiss of death" for these sixes, a very good rear gear ratio is a 3.55--very well rounded ratio--it will wake up the smallish motor and let it run more freely--if you do this first it may save you a lot of motor hop-up spending--it's really a wake-up move. The original '62 Chevy lls were equipped with 3.55s, then in '63 they switched to 3.08s and performance plummeted. I had a '63, and the '62s would embarrass me. Switched to a 3.55 and wow what a difference--almost like going from a two-speed PowerGlide (1,82 low gear) to a three speed Turbo hydramatic (2.54 low gear)when you hit the "go" pedal---OOOOPS--I see now I came 'waaay too late with my suggestion!!


I don't know what kiss of death meant?

I would like to change the rear gears first. I imagine a nice gear ratio for my posi, would wake it up nicely.

Honestly, I seen Summit sells gear set ups for my 8.5 posi, their not cheap.

And..I will admit I have never done a swap with gears. I think you have to do certain things inside there, and something about the large nut on the pinion. I think I would have to pay for that one thing to get done. I know I would not get everything right on that. But yes...I agree, there would be a major difference.

Top
#92392 - 08/22/17 08:19 PM Re: Chevy 250 hp confusion [Re: Lifeguard]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
Originally Posted By: Lifeguard
Originally Posted By: preacher-no choir
3.08 gears are the "kiss of death" for these sixes, a very good rear gear ratio is a 3.55--very well rounded ratio--it will wake up the smallish motor and let it run more freely--if you do this first it may save you a lot of motor hop-up spending--it's really a wake-up move. The original '62 Chevy lls were equipped with 3.55s, then in '63 they switched to 3.08s and performance plummeted. I had a '63, and the '62s would embarrass me. Switched to a 3.55 and wow what a difference--almost like going from a two-speed PowerGlide (1,82 low gear) to a three speed Turbo hydramatic (2.54 low gear)when you hit the "go" pedal---OOOOPS--I see now I came 'waaay too late with my suggestion!!


I assume that is a recommendation for the auto equipped cars, or at least the 2.85:1 3spd through 1974. In 1975 to 1977 they had a 3.11 first gear, and then 1978 and 1979 had the 3.50 first gear. 3.55 is a bit deep for those wide ratio gear boxes.


mine has the 3 speed auto 350 turbo. no overdrive, so I do need to pick the right set when I am ready. I seldom do highway, but there are times I do a consistent 50mph. The 308's really stink.

Top
#92398 - 08/22/17 10:16 PM Re: Chevy 250 hp confusion [Re: preacher-no choir]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: preacher-no choir
3.08 gears are the "kiss of death" for these sixes, a very good rear gear ratio is a 3.55--very well rounded ratio--it will wake up the smallish motor and let it run more freely--if you do this first it may save you a lot of motor hop-up spending--it's really a wake-up move. The original '62 Chevy lls were equipped with 3.55s, then in '63 they switched to 3.08s and performance plummeted. I had a '63, and the '62s would embarrass me. Switched to a 3.55 and wow what a difference--almost like going from a two-speed PowerGlide (1,82 low gear) to a three speed Turbo hydramatic (2.54 low gear)when you hit the "go" pedal---OOOOPS--I see now I came 'waaay too late with my suggestion!!


I don't know what transmissions they were using in the early '60s, but I know the history of the 250 inline in the Camaro and finally made it into a chart:



Assuming they were using the same 2.85 first gear Saginaw 3spd in the early '60s, then for those of us with the later wider 3spd:

Saginaw 3spd std: 2.85std & 3.08 rear = 3.11wide & 2.73 = 3.50superwide & 2.56
Saginaw 3spd perf: 2.85 & 3.36 = 3.11 & 3.08 = 3.50 & 2.73
Sag 3spd hi-perf: 2.85 & 3.55 = 3.11 & 3.36 = 3.50 & 3.08

I don't know how to compare these to the powerglide and TH350, as there is the automatic torque difference? But a 3.08 may be a "kiss of death" for the standard Sag 3spd with its 2.85:1 first gear, but for my setup of '78 3.50:1 first with 2.73 rear it would actually end up being deeper ratio for 1st than the standard Sag with 3.55 rear.

I'm not sure if you can compare the powerglide to the TH350 directly just by the combined ratio. But just doing the math here's how the 1.82 powerglide compares to the 2.52 TH350. Which remembering my second Camaro with a 305cid with a TH350 and open 2.73, does not seem all that hi-po:

auto std: Pglide 1.82 & 3.08 = TH350 2.52 & 2.22(?)
auto perf: Pglide 1.82 & 3.55 = TH350 2.52 & 2.56


Edited by Lifeguard (08/22/17 11:05 PM)

Top
#92404 - 08/23/17 12:37 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
I was giving the observations about powerglides, 3.08 gears, 3.55 gears, and the TH350. So i looked at it from a different angle, comparing the combined first gear ratio based on Preacher-No Choir's observations:

Powerglide 1.82 & 3.08 rear: 5.61:1 combined ratio
Powerglide 1.82 & 3.55 rear: 6.46:1 combined ratio
TH350 2.52 & 3.08 rear: 7.76:1 combined ratio

Preacher said replacing a 3.08 with a 3.55 was almost like going to a TH350. The TH350 with 3.08 is definitely a deeper first gear than even the Powerglide with the 3.55. The math seems to indicate that the TH350 is better than the Pglide/3.55 even with the "kiss of death" 3.08. Not sure how that helps with picking a deeper gear tho?

I'm not sure what axle the Nova has, the L6 post 1970 Camaros all came with a GM Corporate 10 bolt rear and only 2.56, 2.73, 3.08, 3.42, and 3.73 from the factory. No 3.55 like the early SD 10 bolts had.

Top
#92416 - 08/27/17 08:04 PM Re: Chevy 250 hp confusion [Re: TonyPa]
panic Offline
Active BB Member
**

Registered: 01/11/05
Posts: 1496
Loc: Hempstead, Long Island, NY
Lest we confuse this with the very useful "crawl ratio" doctrine for anticipating low speed manners in traffic with standard transmission:
"The 1st gear ratio times the axle ratio should be above 10 for best results".
Example: 2.20:1 close-ratio Muncie with 3.08 axle = misery at 6.8, the 2.52:1 box is preferred here. The 2.95:1 T5 box works well with anything above 3.23.

How does this compare with the auto trans numbers? They all look too low? The missing factor:
1. stall speed means the engine never lugs.
2. the converter's 2:1 (more or less) torque multiplication adds mechanical advantage during roll out.

Top
#92417 - 08/28/17 06:25 AM Re: Chevy 250 hp confusion [Re: Lifeguard]
Blackwater Offline
Active BB Member

Registered: 05/20/16
Posts: 203
Loc: Middle Tennessee
Originally Posted By: Lifeguard
I was giving the observations about powerglides, 3.08 gears, 3.55 gears, and the TH350. So i looked at it from a different angle, comparing the combined first gear ratio based on Preacher-No Choir's observations:

Powerglide 1.82 & 3.08 rear: 5.61:1 combined ratio
Powerglide 1.82 & 3.55 rear: 6.46:1 combined ratio
TH350 2.52 & 3.08 rear: 7.76:1 combined ratio

Preacher said replacing a 3.08 with a 3.55 was almost like going to a TH350. The TH350 with 3.08 is definitely a deeper first gear than even the Powerglide with the 3.55. The math seems to indicate that the TH350 is better than the Pglide/3.55 even with the "kiss of death" 3.08. Not sure how that helps with picking a deeper gear tho?

I'm not sure what axle the Nova has, the L6 post 1970 Camaros all came with a GM Corporate 10 bolt rear and only 2.56, 2.73, 3.08, 3.42, and 3.73 from the factory. No 3.55 like the early SD 10 bolts had.


One thing to remember about the PowerGlide is that it takes approximately 19 fewer horsepower to run it as opposed to the turbo and other transmissions. Years ago, we swapped out a turbo 400 for a PG and picked up .200 second with NO other changes. We even used the same torque converter by installing a turbo input shaft in the PG!!

The Glide isn't as streetable in a heavier car, but in a small, light vehicle and set up right, it presents some interesting possibilities!!
_________________________
Never use a minor caliber bullet on a major caliber adversary

Top
#92418 - 08/28/17 07:10 AM Re: Chevy 250 hp confusion [Re: panic]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: panic
Lest we confuse this with the very useful "crawl ratio" doctrine for anticipating low speed manners in traffic with standard transmission:
"The 1st gear ratio times the axle ratio should be above 10 for best results".
Example: 2.20:1 close-ratio Muncie with 3.08 axle = misery at 6.8, the 2.52:1 box is preferred here. The 2.95:1 T5 box works well with anything above 3.23.

How does this compare with the auto trans numbers? They all look too low? The missing factor:
1. stall speed means the engine never lugs.
2. the converter's 2:1 (more or less) torque multiplication adds mechanical advantage during roll out.


I hadn't heard about the 10:1 combined crawl ratio. It seems to consistently be the rear ratio that I call the hi-perf which is 2 steps deeper from the factory standard ratio:



My stock manual setup yields a 9.55:1 combined ratio which is close to the 10:1. My own experience with the stock engine is that it connects well from the crosswalk, but it is already bogging and wants to shift by the other side of the intersection. Then it rides 2nd up to 35 and starts to complain again until I can shift at cruising speed. So maybe it is asking me for that 3.08 rear. Then again maybe it just wants more advance or carb, we'll see how it behaves when I change those. IntegratedJ78 thinks it wants the extra gear of a Sag 4spd to go to.

Yeah, I knew there was something different with the auto. That makes more sense as to why they never changed the ratios in the TH350 despite the rear axle gearing getting higher for economy in the '70s. The Saginaw 3spd and 4spd manuals kept getting deeper and deeper 1st gears and that was to overcome the change to more highway economy friendly rear gears.

The slush-box just didn't need the gearing change......but so what is the optimal ratio that TonyPA is looking for then if crawl ratio is not important to his TH350?

Afterthought: Is the crawl ratio recommendation based on car tire size then? Because the Camaros and Novas came standard with E78-14/FR78-14/P205-75r14 which measures at 26" diameter. I know the larger cars like the Monte Carlo used the P215-75r14 tires, but I don't know what the standard size for truck tires was then? Obviously much taller.


Edited by Lifeguard (08/28/17 07:19 AM)

Top
#92419 - 08/28/17 04:46 PM Re: Chevy 250 hp confusion [Re: TonyPa]
panic Offline
Active BB Member
**

Registered: 01/11/05
Posts: 1496
Loc: Hempstead, Long Island, NY
maybe it just wants more advance
Yes, many times, but it has to be added manually (and subtracted from the mechanical advance) and carefully - but generally helpful.
26" is presumed for passenger cars.

Top
#92420 - 08/28/17 05:16 PM Re: Chevy 250 hp confusion [Re: panic]
Lifeguard Offline
Active BB Member

Registered: 02/17/14
Posts: 433
Loc: Rockford, IL
Originally Posted By: panic
maybe it just wants more advance
Yes, many times, but it has to be added manually (and subtracted from the mechanical advance) and carefully - but generally helpful.
26" is presumed for passenger cars.


That's what I thought. 10:1 combined crawl ratio with 26" tires. Adjust the ratio accordingly for tire size increase.

Top
#92421 - 08/28/17 05:52 PM Re: Chevy 250 hp confusion [Re: TonyPa]
Mean buzzen half dozen A.K.A. Hank Offline
Active BB Member
***

Registered: 09/23/04
Posts: 5813
Loc: Ca
If you install a TH350 over a PG in any stock inline car or truck, the PG will be slower.
_________________________
12 port SDS EFI

Top
#92423 - 08/29/17 01:16 PM Re: Chevy 250 hp confusion [Re: TonyPa]
panic Offline
Active BB Member
**

Registered: 01/11/05
Posts: 1496
Loc: Hempstead, Long Island, NY
There is one condition in which the PG is more satisfying: kicking down at (roughly, depending on the application) 50 mph will engage 1st (1.82:1) and accelerate better than the TH which can only catch 2nd (1.52:1), so torque multiplication is 21% higher.
Of course, below that speed the TH can reach 1st, and above it the PG has nothing available except high gear.

Top
#92428 - 08/30/17 11:43 AM Re: Chevy 250 hp confusion [Re: panic]
intergrated j 78 Offline
Active BB Member
*****

Registered: 11/16/13
Posts: 449
Loc: chillicothe ohio
If 3.08 is the kiss of death, then the TH 350- 2.73 gears that I have are the Zombie Appolicapse!!! According to The "Gonlicuator" switching to a 2.74 first gear TH 200 won't help much at the drag strip. Jay

Top
#92432 - 08/31/17 06:02 AM Re: Chevy 250 hp confusion [Re: TonyPa]
Tracker64 Offline
Active BB Member

Registered: 07/20/17
Posts: 41
Loc: Pennsylvania
What does the "kiss of death" mean? Mine came stock set up this way?
Straight 6, TH350, with 308's posi.


Edited by Tracker64 (08/31/17 06:03 AM)

Top
Page 2 of 3 < 1 2 3 >

Moderator:  nln6pinto, will6er 
Who's Online
3 registered (stock49, mdonohue05, 53chevy), 35 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
Tuscagi2, Danrush, Billy ray, J Mann, John Forbes
6026 Registered Users