Bumpside

From BumpWiki

The term 'bumpside' is slang for Ford's F-series trucks manufactured between 1967-1972, and refers to the beltline contour, a convex 'bump' which extends the length of the body. It came about as a quick way of distinguishing this era of trucks in conversation from previous or subsequent body styles, such as the '73-'79 era, commonly referred to as a 'dentside'.