The Hurst mounts for the early Hemi's are a generic mount, used mostly in hot rod applications. They're intended to be bolted or welded to the frame. They'll fit any of the first gen or early hemi's, Dodge 270's, 315/325's, Desoto 276/291/330/341's, and Chrysler 331/354/392. Plus any of the poly's that share those blocks, the mounting ears are the same on all of them (width and heights of the mounting locations differ, but the ears are the same). The only ones they won't fit are some of the early Dodge 241 and 270 hemi's depending on the application because some of those were front mounted (no engine mounting ears on the side).