Just build your 346 for boost…forged pistons etc…dont even need to touch the crank. Guys are still making easily 700+ rwhp on stock built cubbed LSx motors.
a 427 would be a no no for boost.
anything over 8psi + a 427 = danger.
if your gonna go with bigger cubes…402/408 is the way to go for the F/I route…most popular simply because it works well.
to the OP…when you get ahold of the dyno sheet, post it up. I would like to see the power curve on it with a smaller turbo than most supras. I bet its gonna be a blast to drive.