From experience, best fit for obvious reasons is ones made for the Chevy/GMC 73-87. Next is the 1980-96 8 foot cap off of a Ford full sized 8 foot bed. The Ford caps are a little wider in back and appear to stick out as the Ford beds don't taper back in like the GM beds do. The earlier 67-72 GM caps fit but some look funny as they don't have the same angle of the cab rear window section. It depends on how picky you are in looks. I usually buy one in the Fall and sell it in the spring but have kept one for several years because I finally ran across one that was meant for the truck and fits great. Dodge caps are a little wider and the newer Chevy 88 and newer are to narrow to fit right. My $.02