The only component that would be on the engine would be the compressor...which COULD be okay if it was sealed up when the engine was removed from the donor car. However, you don't have any idea of how many hours of operation are on it. The evaporator would more than likely be too wide for your GMC radiator and none of your lines would be close to fitting.
Check out the various vendor's systems, how the lines are run with the full kits, and I think you'll be better served to spend the extra dollars up front to get a system that is designed for your truck. That way you know that your system is going to provide you with years of "cool". Hope this helps.
Dave
