The bigblock Olds has far more torque, which is more desirable when working with bigger loads, but either way it's a challenge installing a V-8 engine in the older trucks. The main obsticle will be the steering. Some people shim the steering box away from the frame but I redesigned my whole steering system and relocated it away from the engine altogether. Good luck and welcome to the Stovebolt. If you need more info on the V-8 conversion, there's plenty of people onboard that's done it, all you gotta do is ask,
Scott