I would do donor truck. There’s tons of little parts you will need along the way.... I did the LS 5.3 in my 86. I didn’t go for towing I’m shooting for more street in mine. I also did a turbo setup in mine which is farely easy if a guy has a weekend.
Any advice on getting power to the ground?!...... still have to finish a few things up...these rims and tires are coming off and will be putting tires and rims on that are actually functional.