I've been thrashing on my stock bottom end on 6 psi for years now and I think that it's finally starting to get tired. For my next set up I'm going to a 355 with a built bottom end and mild heads and cam. I'm also wanting to bump my boost from my V1 SQ to about 9-10 lbs with some pulley changes, and add an aftercooler.

My question is what is an ideal compression ratio to go with for my future set up?

 

9:1 is the usual number for a street car.

 

I did 9.1:1 on my motor, for <10psi on a street car I would do 9.5:1, with a FMIC it should run on pump gas just fine

 

^^Yup....

9:1-ish, you should be able to run 10-12psi with out much trouble I don't think, assuming you have a good intercooler, plenty of fuel and a safe, streetable tune.

A lot of guys get in trouble trying to squeeze every HP out of their motor, run it on the edge of safe A/R trying to get another 10hp on the dyno sheet. One thing goes wrong and the motor has vented pistons..

Plan on up-ing your fuel system to keep up- and perhaps bumping up your injectors to be safe, depending on what your goals are. I think a purpose built FI 355 should easily be able to make a safe 500 rwhp without much trouble.