My oldest bro. bought a new '65 GMC . Him and I drove to S. Cal. and Mexico that year.
283 with 3 spd column shift. These colors
https://classics.autotrader.com/classic-cars/1965/gmc/pickup/101922299
He has a build log with more details.
I have it on page 7.
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/project-x71-reheating-stampies-leftoversfcfc/177534/page7/