T3 turbo's
 

what's the diff between O, P, and Q trim compressor wheels

Also about how much HP will 2 T3's (60(trim) compressor .82 a/r turbine) suport on a 355?

Re: T3 turbo's
 

I'm guessing you mean the trim on the turbine not the compressor. The different trims for a given A/R housing will change the flow capacity and possible turbine speed you can reach.

Problem is, even 60 trim T3's will be too small for you. Even at 7 psi you'd be way off the compressor maps for both the standard 60 trim and the super 60. On a reasonable 355 setup you'd need about 30 lb/min from each turbo at 7 psi, that's way off the usable efficiencies for any of the big T3's.

You're better off looking for a pair of T04's