OK, so I had a thread in the blown and injected thread asking about supercharging my 250 in my '69 C/10 truck. As I researched and got all of the helpful info, I realized that for this particular application, I would prefer to keep it naturally aspirated. I am planning to do some head work (valves, lumps, etc.), put in a cam, and probably bore the block .030 over. I will also be running headers. My first instinct was to just grab an Offy intake and 4 bbl from Summit or JEGS, but I have heard a lot of interesting talk about usingtriple side draft Webers. If I did this, I would probably try to buy it all in a kit, like the one Clifford sells. I was hoping to gather all the info I could before I decided to spend $6-700 on an intake and 4 bbl or bite the bullet and spend over $2000 on the side drafts. The money isn't the issue, I am more interested in the performance and reliability factors. I have heard that the side drafts are better for performance, but can be more finicky. I am looking for pros and cons, and what is really involved in keeping the side draft system running right (I would use good linkage). I don't drive the truck daily, but would like to keep it where I can drive it whenever and wherever I want to. Sorry for the long windedness, and thanks for the help.
Matt

The side drafts will produce more tq over the rpm range. They are expensive as you have found. They are harder to setup and will be less forgiving.

I would suggest a turbo setup. Give a blow thru carb 5-8 PSI and smile! Easier to tune and maintain.

Almost anytime you can have a straight shot @ the valve the better. A side draft intake will give you a straighter shot @ the intake valves.
Just look @ modern motorcyle cyl heads w/there pretty much straight ports to the intake valves.
1000 Cc/1.0 liter bikes making 180 HP.

You might want to look into side draft throttle bodies & fuel injection.
Mike Kirby makes & sells TB's & mechanical fuel injection.

Example: http://www.borla.com/products/induction/ThrottleBody/ThrottleBody2900.html

My friends sells TWM throttle bodies & SDS fuel injection systems if you are interested.

I have an SDS system for my inline, not running, but I got it.

With F.I., it will make tuning much, much more easy do so.

Don't get me wrong, Webers are great, but they are old school, you need a lot of time & patience & extra jets, emultion (SP) tubes etc to tune your engine. That can get a little spendy.

W/an SDS sytem, it's is really easy to opperate, not laptop needed.

http://www.sdsefi.com/

If you want to learn more about the TWM throttle bodies, & the SDS fuel injection & possibly the J&S safegaurd
http://www.jandssafeguard.com/

You can contact my friend Ray.
Here is his website: http://www.american-pi.com/corvair/corvhome.html

MBHD

How much more HP did they make over a 4 bbl carb?

MBHD

Webers aren't something you finally get dialed in forget, they need adjustment periodically and like Hank said, make sure you get extra fuel and air jets, emulsion tubes and gaskets. Living in the south like we do, you will see a temperature difference over the year be 100° in the summer and near zero in the winter. The temps in SoCal doesn't vary that much all year, so you might can go for longer spans of time without having to adjust or readjust for temp differentials if you lived there. In the south here, it can vary 50° in the same day. I'd buy some used to see how you like tuning on them before throwing down 2 grand for a set new. You might like them, but then again you might not, so find out before jumping in too deep.

Thanks all! Hank I followed some of your links, the sds one said it wasn't for siamesed ports. Would that be a problem with our heads? I thought that the intake ports were siamesed. I also have emailed tlowe for the dyno results b/c I couldn't find them on here. He said to give him a call, and I haven't had time to do it yet. CNC, I wondered about our climate being a problem.I want something that is almost worry free, so a 4 bbl might be a better choice, but man I really dig those triples! Some of those efi systems seem about as expensive. Will they yeild significant increase ove a 4 bbl? Also what head work do you all recommend> i am thinking I am looing for a hot street motor, and Santucci says to upgrade the valves, and lump the ports. I don't know if I can find a machine shop around here that knows about anything besides a small block. Does anybody sell a head that is ready to go?

Have you been to http://www.12bolt.com ?

An SDS system will work with siamesed ports.
As Tlowe found out his Holley EFI is not optimal for siamesed ports either.
They are batch fire systems & work the same way, just the SDS you do not need a laptop to tune.

Tlowe installed port deviders which helped the idle, better economy, but it also severly makes the intake port window really small.

I had tested port deviders years ago on a flow bench & was so disappointed with the low flow I never installed them on a engine. I even widened the roof of the intake ports like I told Tlowe to do, they still did not flow well.
But, with a turbo or supercharger, even though the cyl head cannot flow good, the air/fuel mixture is being forced into the engine, so the results will not be as bad.

Running 3 side draft Webers or EFI T.B.'s are going to give you the best power over a single 4 bbl intake, Clifford or Offy, by a great margin.

I have run 2 bbls 4 barrels Offy's & Clifford intakes w/all different camshafts & compression ratios. It is the best set-up to make the most power period.

http://www.sissellautomotive.com/

MBHD

tlowe, I have felt my wallet itch more than once looking at that 12bolt site! MBHD, where can you get the throttle body and manifold?

My friend Ray can get you the EFI throttle bodies. Also sells the SDS EFI for your 6 cylinder. http://www.american-pi.com/corvair/corvhome.html

http://www.sdsefi.com/

Manifold http://www.cliffordperformance.net/Merch...egory_Code=C250

Don't be surprized if the manifold needs surfacing, unless there Q.C. has gotten better.
I sent back 3 manifolds, then gave up & had my friend machine the last one they sent me flat.

MBHD

what size Webers are we talking about, and, is that venturi diamter or is that throttle butterfly diameter

The first numbers in Weber carb nomenclature is size of the butterflies measured in millimeters. The 40 DCOE would thus have 40mm butterflies. The "DC" stands for "doppio corpo" or Italian for "double throat" (ie. 2 barrel in english). The "O" means "orizzontale"...Italian for "horizontal". The "E" is not consistant in it's meaning. It could mean anything from electric choke to trapezoid bolt pattern to die cast carb.
fasteddie250sprint

OK MBHD. Thanks. Got an email in to the corvair guys. What kind of head work would you recommend for a street strip type application?

I would run 1.94" intake valves, 1.60" exhaust, lumps installed, performance valve job, not just 3 angles,back cut the valves, bowl porting,short & long turn radius' worked over.

Valve guide bosses can be contoured, but do not make them any shorter. They are too short as they come from the factory.

Exhaust port, ported all the way through & opened up.
Intake port, just gasket match,(IMO, you do not really need to open up the intake port window/gasket match),It's up to you though, don't go any bigger than the gasket, or you will lose port velosity, this is critical .

Unshroud the chamber wall on the intake.

Oversized valve springs, cut guides for seals, not PC seals, the better softer ones, name slips me right now, kinda blue/gray in color,,,, ohhh ,, brain fart. Vel,,, del??? Anyways...
Surface the head for a good seal.

It would also benefit you to run a zero deck & even a positive deck,need to get all your measurements correct though.

You can ask Larry AKA twisted6 , Mike Kirby, Mike Barile, Tlowe etc, for more info & pricing.
Cyl head work is where you will get most of your power from ,so if you can, don't skimp on the cyl head. Or your induction set-up for that matter.

Hope this helps.

MBHD

Thanks so much. I have read Santucci's book as I said, but there is so much stuff in there it is kind of overload. It helps to be able to get advice specific for my application. I am planning on getting in touch with tlowe, I understand they have sort of a head prep menu over at 12bolt. I talked to my neighbor earlier tonight, he used to run a speed shop in town with his brother, and he recomended a guy for head work. These guys are serious Mopar guys, and anybody doing head work on Mopar should know their stuff. I bought a 70 challenger one time from them, with a 440, sold it to help pay off the house. Regrets, regrets...

I know the head and intake is where power is gained and lost on these sixes, so I just want to be as thorough as I can before I start. You can always slow down, but you can't unf@#* something up.lol

If guys are not familar w/Chevy inline 6 cyl heads they can port through into a water jacket. They need to know where & how much they can port.
Unless they sonic check how thick your casting is & the port walls, I sorta doubt they are willing to do that for you & not charge an arm & leg sort to speak.

I would take your cyl head to a shop that has done many 6 cyl Chevy heads.

Just my two cents on that thought.

MBHD

I TOTALLY agree. I might just pack the thing up and ship it to 12bolt or Sissel's. It is expensive, but often it seems as if you get what you pay for.

Found a machine shop fresh 194 head on cl for $400. Havent been able to talk to the guy yet, but it has new valves. will the headers and intake and valvecover off the 250 fit the 194?

Here we go again, the 194 head should probably be your last choice. If you look at some of the other threads you'll find that in stock form it'll rob power from your build. A fresh from the machine shop 250 or 292 head will produce more power in stock form than a 194 head and with any of the modifications you can do to a 194 head you can do to the other heads with similar results and still out perform the 194 head. I think you should be able to find a 250 or 292 head in the $400 range without any problems.

If you are looking just to slap on a cyl head w/1.72" intake valves & want a bump in compression that will definatley work.

It will bolt right in & headers, valve cover etc will all fit.

Mill the head & you can seriously bump the compression up even higher w/out having to change out your pistons.

If you want some chamber work (larger valves?) done so it will flow great, send it to Larry or Sissells.

MBHD

Thanks, guys. I think I will be better off just getting my head built right. I had jst heard they would fit, and wondered what would be the up/down sides of it. I definitely plan to spend a large part of my money on te headwork, because that seems to be where the power is mad and lost in these engines.

MBHD, I am planning on changing my pistons and boring the block and balaancing the crank. I might even uupgrade my rods, if I need to. I would hate to bump up compression on a bottom end that hasn't been touched since 68-9. I am definitely going to upgrade the valves and lump the ports, so it would probably be better to do it to one of the good 250 heads I have, instead of wekening the 194 even further. Guy selling it says his block cracked, but he didn't know till he was far enough into his build that the head had been done. So maybe the head is weak, too??