As the title says im looking for advice on a kind of mild performance build for my 1979 cutlass supreme, its a stock 350 olds. Right now im looking for headers, thinking of a new intake manifold and carb /air cleaner next as it still as the original snorkel. Possibly a new diferential. Ive also heard that the 350s had the worst flowing heads and to look for some heads off of a 403, is this so? Also any other advise on increasing the performance on my low budget build would be appreciated. Thanks, Sean.

 

Depends on what yr the heads are. 72 and earlier are better than any stock 403 Heads. You probably have a low compression motor. Headers are a good idea. Do you have to worry about emissions? The intake, carb and air cleaner wont help much. Aluminum intake will lighten it up some. Cold air intake helps. Rear end gears will help depending on what you have. On a low budget there's not a lot that can be done. Can You do most of the work yourself?

 

I've got a set of heads off a 330 with big valves...that'll bump the compression up. The holes are drilled for 1/2 inch bolts. As far as flow.... Small block heads are close enough that it shouldn't be a deciding factor of which ones to go with... 3, 4, 5, 6, 7, 7a. Intake will help. Gears will probably be the best thing for it. 3.42 is a popular choice among guys with a 3 speed auto.

 

And i guess i should clarify some. The 350 and 403 heads will flow pretty similar. It's the combustion chamber size that's different. 403 combustion chambers are huge and lower compression too low for performance. Some 350 heads have large combustion chambers too. It all depends on how much performance you want. Daily driver? Race car? Weekend driver?

 

Headers, intake and carb are good choices maybe want to recurve the distributer, if the engine is in good shape I wouldn't mess with the heads. Putting a gear in the rear end is a good bang for your buck if you can afford worse gas milage.