Re: whats the difference between GMC and Chevy\\?
70 was the last year for any noteworthy differences between the two. That was the last year for coil or leaf options... 305 V6... blah blah blah.
You could still get 5/4 ton GMCs through sometime in the late 70s... couldn't do that with a Chevy.
After that, it was pretty much trim differences. GMCs usually got nicer everything and from 82-87 had better quality control (even though Chevys ran down the same line). I know that GMCs got better quality control... because my grandfather was the quality control foreman for those years for second shift. GMCs continued with the "better trim" up until they discontinued the Top Kick line which they later brought back.
Now they've gone back to the olden days of "a workin' man's truck" and call it "professional grade". I'd like to see the GMC line go back to work trucks with cool options like AC delete, standard vinyl floors, drain petcocks in the floors, everything but the basics delete, and of course they'd have a SFA.