Originally Posted by SSSnoop

Um, the LS4 is dimensionally different, and what is it - technically 2 ci different? - but I think you're missing the logic here. You can get a cam ground for the LS4. You can work the heads, and you can make mean power with the LS4 - every bit as you can make with the truck block. And if you're lazy, you can always turbo the shizzle and it'll accept at least a nominal 8 psi without a hiccup. The LS4 isn't some retarded step child here! They may be not very well supported as the rwd blocks aftermarket-wise, but you can't count them out as something other than a block with serious performance potential. Sorry.

Originally Posted by GarrenT

G8 GXP's are fast and can be built but the Grand Prix GXP have a stock 5.3 that's quick but nothing compared to a SC built or TC Cobalt. You'd wreck the kid. Good fight GXP.