Sorry, should have mentioned it has to be an auto. I believe the older AOD trans is hydraulic so getting it to work won't be an issue other than fitment. As for chevy swaps, I would do a 5.3 or 6.0. Truthfully, All its gonna be is a putting around truck it doesn't need to make nasty power, just get me to the camping spot or fishing hole. My Subie, once i get the overheating issues lined out, will be the fun toy! :D