Compression Ratio and cam questions
 

Hi, okay i got a 67 camaro, 355. 9.2:1 compression ratio with keith black forged pistons. i got 2.02 heads and a fresh port and polish. and a stock cam..

i got bewteen 350-375 horsepower flywheel. and say 13.5 in the 1\4 mile.

If i bring the compression ratio up to about 10-1 with a set of domed pistons, and throw in a nice .234 cam. what would this do to my horsepower, times rough guesses please. and also what would it do to gas mileage and streetability, i get 10 mpg. currently.

I assume you have flattops now? I went back and calculated your compression ratio assuming KB flattop hypereutectics, .039" composite head gasket (9cc) and 64cc heads and I get 9.8:1. 67cc heads and it's 9.5:1. 72cc heads and it's 9:1. Be sure of your compression ratio before you make changes. Just FYI.

If you truly have a "stock" cam in there currently then you really don't need to go wild to get some impressive gains across the board. A stock cam will usually only have about 185-190* of duration @ .050. Compare to that and you'll see that even most "mild" performance cams are still significantly wilder than stock.

A Crane Cams Energizer 272 (216/216* .454/.454 lift 110* LSA) will make for some impressive mid-top end gains with very little loss on the bottom end. Make SURE you use the valve springs they recommend with this cam- stock springs don't stand a chance of controlling this cam over 5000 RPMs. Mileage should be about the same, give or take, depending on how well you tune it. Idle will be just a smidge "choppier" than stock but no lope. Should pull about 16-17" of idle vacuum. No problem with power brakes. This cam will work well with compression ratios in the 9.0-10.0:1 range, tending towards 10:1 for best performance.