Originally Posted by J@meson

I sugest the 5.3 due to the lack of cost to aquire one. The LS1's are treated like there made of gold on the resale market. Altho you said the swaps comming out of a 98 formula, so I assume your going with a LS1. The T56 in that car is not a viper spec trans jus a regular run of the mill T56 and factory ones handle about 450lb/ft (factory rating as a stock LS1 can trash one) whats working against you is using a heavy car but then again Gto's are as well and they make due. Just dont abuse the trans with powershifts and hard launching and you will be ok.