Inliners International Forums General Discussion Hi Performance Chev 250 intake/carb

Any advice to new guy restoring 66 Chev PU w/250 regarding intakes. Thinkin Clifford w/Weber 38/38 or Offy with a 390 4 Brl.Hate to tear out the new exhaust former owner installed. Stock manifold with little thru muffler.Sounds nice. But then again Clifford or Fenton. Also installing 2004R Tranny. All engine work to begin Oct.

Don't use the Clifford unless you want less low end grunt.

Offy is better for the everyday street engine,sends a stronger signal to the carb,better mileage etc. It's been proven on my street car many times.


Use Toms cast iron exhaust manifolds http://stoveboltengineco.com/acartpro/product.asp?productid=171

MBHD

Thanks MBHD-
Cost less too.
What carb do you reccomend?

tp

The 390 Holley carb (list 8007) is a great fit for 250 and 292 engines.

The Offy vs Clifford 4 BBL debate is still out. I performed dyno tests for this reason and found the Clifford was better. There are in car tests going on now. Will know soon.

Thanks tlowe

Appreciate feedback. Kind of an old goat here and been out of the fun car stuff a lot of years. Corporate America ate up all my time for cars, fishing and hunting.
Wife and I are really enjoying car shows, and this old 66 PU project.

Thanks again
tom

Tom Lowe,
Do you have a torque curve for a stock 250?
I've got the one from the convention with the Offy manifold, but a guy over on the Stovebolt forum was looking for a bone stock one.
I think it would also be useful to Tom TPZ here to see where he's starting from.

regards,
Leon

I found that on a daily driver my 64 SS liked the offey better over the clifford Both intakes ran a 600 holley.I also did this with it being stock. and with a crane RV cam back in 84.The first or earlier test i did with the PG & a sag.3speed & 308 gears. The RV had a 4speed. also as a side note I got better MPGs with the offey over the clifford.If your looking for the better of Both worlds(meaning low end to High end.) go with the clifford and Install a lump kit. This will give more of the low end back you lose with the clifford.Also stay with the 4port carb plate.Not a open port plate.

All
I really appreciate all the feed back guys. I'm kinda letting all the info I can gather cook over the next month. Busy Sept and my son is using the PU in Seattle during a remodel. In Oct things will be getting seriuos. The 250 runs nice now but with not a lot of guts. We'll dig into it then. If the 250 checks out well my plan was to keep it, add intake and exhaust system. If not, I might find a 261 or even a 292. I want to install an automatic, get her lookin better and hopefully tow a small antigue camper. I would install a T5 but this old beat up set of legs need an auto. The football and runnig have made it difficult even for my son to handle in traffic.
Thanks again and keep the info comming if you are up for it. Appreciate all the feedback.
TPzshop

Sweet, are there going to be tests w/a 194 cyl head vs an big chamber head on a car also?

When you have proven that the Offy intake out accelerates a Clifford intake on a 250,what type of equipment are you going to use?
I have a Beltronics FX2,, http://carjamz.com/zen/index.php?main_page=product_info&products_id=1505

It works very good & is very accurate.
Me & a friend did performance runs on the street w/the FX2,then (two different cars) my Turbo CVT Audi & his 2004 turbo Jetta. ,we went to the track & really could not see any difference in times we measured.
0-60' ,0- 60 mph etc.330' 1/8th 1/4 mile are pretty much the same times as we tested on the street.

Does not cost much & you do not need to go to a track & spend more $$$$ Just a thought.


The Offy will have better street manners,better mileage,better throttle responce & so-on. The carb will carburate better.
the engine wil get into the powerband faster,have an ability to spin the tires sooner. Theres more.



MBHD

So when are these in car tests going to be done?

All these tests have been done years & years ago by many people including myself.
If anyone want's to know what works better for a certain application,all they have to do is ask here & they will get an answer/s.
It's just that easy.

For an example,250 CI L6 ,a guy has 11:1 compression 230 duration cam @ .050" .550" lift on a 108 lobe center
3000 rpm stall 410 gears. 3000 lb car. 500 CFM Edelbrock AFB or AVS carb
That person wants to know what intake manifold would work better for racing 1/4 mile ,an Offy or a Clifford.
Just an example:
Another guy has a 194 CI L6 has 8.3:1 compression,cam is .450 lift,duration @ .050 is 200. 323 rear gears, stall is 1200 RPM PG trans,car weighs 3500 w/driver.
Main concern is gas mileage,& wants low end torque,, rarley will see above 2500 RPM, daily driver.It's just a driver,wants to know what manifold is best for him?

MBHD

I had a '67 half ton short wide bed with a 250 standard three speed (2.94 LOW GEAR) and a stock 3.70 gear. It had a cold clifford intake and used a Holley "economaster" (450 four bbl talk cfm) for a long time- then went with a model 1850 holley (vac. secondaries 600 cfm) both were really streetable and with a heater hose zip tied to the bottom of the clifford during our mild texas winters, even cold weather operation was acceptable. If I had a Carter AVS (or whoever makes them now) I would have really wanted to use it- AFB types are good dependable carbs-and the AVS has adjustible secondary action like a Q-Jet. Also had Heddman/Flowmaster exhaust system, yet I dont think it would get past 5000 rpm in neutral- stock cam is mild! (or worn out). The motor with some fast advance springs in the standard ignition and made it very crisp- but at 250 inches its at a disadvantage to a lot of stuff, but not in noise! They cant hear their motors to know when to shift, and you can set off a whole parking garage full of alarms with one good rap! With a fairly low gearing almost any intake will be o.k., but as you get into higher gearing (less rpm/ mph) an offy may appear to be better, but you still have that big old headbolt boss in the head roadblock no matter which intake you use. My experiance with the clifford was good.

edski,

It sounds like you had not used an Offy intake?

Just want to make sure,because I think if I had only used a Clifford intake & never used an Offy for comparision,I most likely would had said the same.

I to never had cold weather problems w/either intakes here in So-Cal.

I will also add,when me & a friend first started putting together his 250 L6,he had used an Offy intake manifold,Clifford headers ect,into a 69 Camaro(which I own today)

The Camaro had 3.08 rear gears,saganaw 3 speed on the floor.Carter 500 CFM carb,large chamber head, stock valves, standard valve job,stock type .030" over pistons,cam was american cam. .510 lift 280 advertized duration 110 lobe center.

It ran OK,high 15' low 16's in the 1/4 mile.

One day I had a neighbor selling a Clifford intake w/a Holley 2bbl carb 350 CFM,picked it up for $20.00.
I was really excited about the price I got it for & could not wait to put it on & try it out.

I used the same carb 500 CFM,,well,to tell you it did not run that well down low would be an understatement.
I swapped jetting metering rods,bought the Carter complete jet kit,swapped springs & so-on. Installed 4 hole spacers,open spacers,2" 1" you name it.
I also used/tried Holley 600 CFM vac carb,Quadrajets,Thermaquad,Carter AFB/s AVS" 400,500 -625 CFM (friends had Mopars) Rochester small & large 2bbl carbs.

All this work & I was very disappointed.
Even tried the 350 CFM 2 BBL Holley,that helped the low end response,but the top end pull suffered.

W/the Clifford intake & all the 4 bbl carbs I tried ,it did not carburate as well as they did w/the Offy.

Raced against a friends car,& my Camaro was indeed slower & you could definately feel it.

Put the Offy back on,better throttle response,raced against same friends car & it was back to being even as before.(thats' the main reason I wanted to put on a higher performance intake manifold than the Offy,I wanted to pull away from my friends 69 Firebird 400 CI Pontiac(weighed 3700+ lbs no driver) ,we were always dead even w/the Offy),put the Clifford on, back to loosing too much power again.

I then realized, I would need to do more drastic measures if I were to beat my friends 400 Poncho.
I got 4.10 posi rear end,TH350 trans, 3500 stall converter,actually only stalled to 2700,then @ that point I used the Clifford intake(made more mid to top end power than the Offy)
Fianally ,got faster out of the hole & I could hold him off on the top end.

It was not tell much later I installed 3 Side draft DCOE Webers & Clifford intake,which was the ultimate power maker. Everywhere, in all RPMs it made more power period!



Hope I didn't bore you.


MBHD

Never had an offy, six cylinder parts too hard to find, so run what you brung. But
did have a corvette set-up on a .060 over 261. Nice setup, ran real good, made good intake noise, rivaled the exhaust note.

Not boring at all. Like to hear experiences, only way this old goat learns.
I have a mechanic now thaat sounds excited to help me get the Pickup the way I want. One of the first things he said was the 2004R tranny is going to take some of my horespower. He wanted me to put in one of those Belly Button 350s. Meeting him tomorrow night to go over my dream sheet. Going to be fun.
I appreciate all-- thanks

TPZ

I dont see how a 200 can "rob" you of more hp than a 350 th, you will be giving up a bunch of off the line jump by going from a 3.06 low gear (not to mentionthe n o.d.) to a puny 2.52 low gear in the 350th. Not quite as bad as the relationship of a 350th to a powerglide though, and thats an amazing difference- dont go with a 350 unless there's a lot of money involved.

I think the reference was to how much extra power is used internally due to more rotating parts.

having re-read your post reminded me of my early body chevy ll's, and its hard to believe you could run that good with any combo with 3.08 gears-that was the culprit. And I can see where the offy would be the far better intake. My first '63 chevy ll (stick) had a 3.08 and a 194, I ran a buddy's (four banger) chevy ll with a 4.11 6.00 x 13 tires (mine was an SS with 14" tires), he killed me off the line and it took a long time in 2nd to pass him. I switched to a 3.55 and it was a new car,stout and at least 15 more mph in high gear it would pull 5000 in high. Much later a got another '63 chevy twice SS and it had a 230 motor with a3.08, still a dog (all this with 2.94 low gear three speeds} , put in a 3.55 and same story.) The 230/3.55 car would stay with a 195hp/283 equipped chevy ll (w/ 3.08)from 50 to 70 mph. Those cars really liked a 3.55 in their stock (split manifold, lots of spark advance) tune. Later ran the 194 car with a 4.11(rear ends were the same as '55 thru '64 pass, 'vette cars- easy to swap out 30 min. or so) it was really quick but high gear would top out a 95 mph (same as with 3.08 gear) Any way when you swapped to 4.10 gear this I feel is what really woke up your car (other stuff would come into there own with this gear.) now I hope i did not bore you!

The Camaro always had Clifford headers & dual exhaust when my friend got the 250 rebuilt.
edski, did you use stock camshafts in your 6's?
You story did not bore me,good times & memories.

With he 3.08 rear gears it was not that slow with the retreaded Caldwell sticky tires & the low first in the 3 speed,but 2nd gear sucked!


MBHD

Naw- my new Mechanic friend, the first thing he said was or meant was the 350 SB engine, I convinced him I want to stay with the traditional inliner. He respects that and thinks we are going to have a barrel of fun. We are kicking around the idea of having a local well known engine shop and race team build a 292 for me.
He did say he has experienced reliability issues with the 200R4 vs the 700R4 tranny. He's been wrenchin traditional old stuff for over fourty years.

TP

Guys with turbocharged Buick Grand Nationals & T-Types all have the 200R4's in them stock.

Stock the engine actually makes about 300 HP.
Buick guys like thier 200's & many run 12,11,10 even 9 second 1/4 mile times.It seems they stay together when running 12 second passes,(their weight 3600 LBS)..any faster,than 12's,they need beefing up accordingly.

Need to find a person that knows the 2004r's.

I never liked the big gear space gap on my 3spd manual trans & I am not a fan of the big gear drop/spacing of the 700R4's,unless you are super or turbo charged,then the engine can somewhat push the car through the gear spacing w/the added torque from the forced induction.

Early 700r4's had reliabilty issues also. 28 spline ones.

I have a 4l60E,basically a electronic controlled 700r4,w/a SBC 350 w/350 ft lbs of torque,,,my 350 has a hard time pushing through 2nd gear.I don't like the gear spacing for my V-8 either.

If you are running a normally aspirated L6,I would never run a 700R4,gear spacing just plain sucks.
A 700 will take off good in first,but then falls on it's face in 2nd gear.

Two cents thrown.

MBHD

Yes that kinda reinforces what I have gathered.
Appreciate your feedback.

TPZ

dont the 200's have the same ratios as the 700's- is there a weight difference to speak of? some day i want a t-bucket with a healthy 292 (maybe turboized)and a o.d. automatic- but I want it light maybe 1400 lbs - free horsepower!

The 200 is smaller and lighter, the 1st gear is slightly lower (less torque multiplication), the 1-2, 2-3 shifts are closer, but the shift to OD is wider.
The 200 in the GN has many special parts - don't expect a generic 200 to hold up to big power without some preparation.

Some comparisons on my site: http://victorylibrary.com/mopar/aod.htm

If you have/had a 3 speed manual,muncie 4 speed, powerglide,short tailshaft th 350,then the 200R4 will drop right in,no need for a different driveshaft.

Relocation of transmount needed though,not that big a deal.


MBHD

Are you sure I will not need the adapter from Stovebolt?
I read about shortening tran nose shafts,advertised adapters,
the rear of the 6 bangers being the same as small blocks etc.
What's a dummy to figure.

TPZ

No adaptor I promise.