LS3's can make 400whp with just bolt ons. LS2's can get there, if they try hard.Aside from cutting a hole in the hood, I think those numbers are low. I thought there were cars making 400 hp with just bolt ons. I would have though he would have been in the mid 450 hp---danfigg
an LS1? eh... no. 340 best. especially with that crappy stock truck cam.
OP still has factory heads (although they are 231's) and a factory intake that is better than the LS6 he had on there, but not as good as a FAST. Not sure about his exhaust setup... but, I think his numbers are fairly typical with the mods.
a FAST and CnC heads? he'd be over 450 me thinks. add a few more "every last bit counts" mods and he'd have a little bit more.