I have a line on a 86 Full size GMC Jimmy that was originally a diesel, but the owner before this one pulled it and replaced it with a chevy 350 small block. Its Automatic and a 4x4, it has 140k miles on the chassis, unknown miles on the engine and trans, and the only thing that's wrong with it is it needs a heater core. I'd love some input on it, is the 350 small block bad or good on this truck? Thanks so much for your help. I think this is a good first truck for me and my dad agrees.