A vette is somewhat heavy, fiberglass weighs a ton-I should know I have a C4. It isnt nearly as heavy as the truck is but still heavier for a sports car-thats why back in the day they didnt compete in prostock racing.

If you wanna do the LS it is gonna cost you-gonna need the drivetrain outta a 1500, swapping in an L98 or LT series would work as well. Heck any chevy smallblock 350 will fit easy.

Anyway, I would go with the 4.3L it has alot of power for the size and you will like it. I drove an old 1500 work truck with one and coulda sworn I had a smallblock v8 in it, it can really move.

 

LS6 if u can afford it.go further.