^^ funny... because i've been following a guy's build for a few years who started with a 4.3 then went to a 454BBC then to a 8.1 - all with a bone stock NV3500 and beating the crap out of it every day. then he slapped a turbo on the 496 & the trans is still kickin. even the project manager for the Joe Gibbs Silverados personally told me they didn't worry at all about the blown 4.8 pushing this trans.

and all 1/2 tons used the same 5-speed: the New Venture 3500. i've been running a bolt-on 5.3 with my 4x4 for 3yrs now with no issues.

and to the OP - make sure to get the purple jumper wire out of the fuse block for the clutch safety. click my sig pic & scroll down to where i talk about the details. and my personal opinion is that if you're swapping a 2WD from scratch, you'd be better off using a T56 from a GTO or F-body