crazy??

instead of doing a complete 6G74 swap into my N/A, i was wondering if my block could be bored enough to accommodate the 6G74 3.5L pistons?

nope. the max the block can be bored to is around 3.15L

what would the power differences be with the 3.15L compared to the 3.0?

probably 10-30 hp. but if you're gonna rebuild it, do it right. if rebuilding, i would consider forged pistons, cams, etc. but that's not cheap.