How much more power would I get from a 350 - to a 355. I plan to supercharge the engine 12 psi. I'm looking 500-550rwhp range. I was just going to have the pistons/cam and rods changed but if I were to do a 355 how much more power would I see. A estimate around

 

Not enough to mention. Build the bottom end and remember that the power comes from the heads/cam.

 

I would think that most people only do a 355ci because the pistons are easier to get. There aren't a large variety of 4.000" pistons out there incomparison to the 4.030". The good thing about the 350/355 is the spin-ability of it. If you get the good rods you can out do a larger cubic inch motor in rpm.