What is the difference between a Chevy and a GMC?

Not much anymore, just trim and interiore are usually different. Back in the day a GMC was just a little fancier than a Chevy, just like Ford was with Mercury. Also, GMC used to use different engines than Chevys, but I think the last of this was in the early seventies, but even in the sixties you could find Chevy engines in GMCs. I could go on for forever with the history, but I think this answers the question well enough. Hayden