'70 350 2-bbl engine mods

[woz442]

I have a '70 Olds Cutlass Supreme w/ 350 2-bbl automatic single exhaust. I believe this engine is a 250hp model with 9:1 compression as it is original with stock rebuild. I have, however added an HEI ignition.

Does anyone have experience with mild performance modifications to this configuration? Specifically, I want to add headers, dual exhausts, a 600cfm carb on a Edelbrock Performer intake and want to know if I am wasting my time by keeping the stock cam with these mods. Not a race car mind you, but I want to approach the 310hp of a W-31 as economically as possible. Thanks.

Tom

[71 W-30]

My daily driver is a '71 350 Cutlass that came from the factory with a 2bbl and single exhaust. Adding a mandrall bend H pipe dual exhaust, Pertronix kit in the distributor, and changing to a stock cast intake and quadrajet did wonders for power and the gas milaege went up.

Headers will help more, but don't go with big tubes. There are some 2" SBO headers out there, but a smaller tube will work better with the changes you are talking about. I would recommend an H pipe or an X pipe between the headers and mufflers. Kooks makes the nicest headers, but they are not cheap.

1971 was when all Olds V8s went to low compression and they changed from gross to net horsepower. The 2bbl was rated at 160 and the 4 was 180. After putting on the stock cast iron intake and quadrajet, I beleive the 20HP difference. A Performer should work even better with the mods you are making. If nothing else, it'll lighten the car 40 pounds or so. Get the regular Performer if possible. The Performer RPM has larger ports that are mainly designed for big block heads. I kept the cast intake to keep the stock look. I'd say that a 600 carb is about right, but I'd go with a vacuum secondary.

The cam for most '68-'72 a-body 350s is a mild .400 lift cam. The manual trans 4bbls got the .474 lift, 285/287 duration 442 auto cam. The W-31 got the early W-30 .474 lift, 308 degree cam, but they had a lot more compression. I've thought seriously about changing cams when I replace my timing chain this summer. Something like the .448 lift '83-'84 H/O cam would work well in my car.

You will still benefit from the modifications you are talking about with the factory cam. You can get more power from the mods with a bigger cam, but your gas mileage will suffer. You wouldn't want to go that much bigger with the cam with the stock converter, gears and low compression. The changes you are talking should wake the car up quite a bit.

Terry

[woz442]

Thanks Terry! I've actually only had big blocks in the past with the exception of an old 283 in a 63 Chevy, so I want to keep the low end there. I would be using a regular Performer manifold and not the RPM version, I understand those differences. I am alos looking at an exhaust with an H pipe as you suggested. I also agree with your suggestion about keeping the pipes reasonably sized but headers and exhaust.

Any good sources out there for the Olds small block Gold hi-temp spray paint? I thought Year One used to carry it but couldn't find it anymore. Thanks again.

Tom

[davidd]

I have a 70 Cutlass 350 w/ 2 bbl carb. Here is what was done.

Edelbrock manifold & Holly 600 CFM carb

Edelbrock Cam 214/224 new lifters, rockers and push rods

New headers w/ Flowmaster 40's

While engine was out I also had a new Edelbrock Timing chain and hi performance oil pump installed.

The difference was like night and day Total cost was slightly under $3,000 but money well spent

If you have the bucks and don't have too many miles on the engine go for it.

[71 W-30]

Fusick has gold engine paint. Supercars Unlimited should have it as well. Supercars' bronze 400 paint is closer to the correct color than Fusick, but the gold is probably about the same. Great people at both places!