Hy marvin ribbich, as 78buckshot has said it is more a matter of having the correct bellhousing to mate any engine to any transmission. In the mid fifties heavier trucks manufactured by Chevrolet and GMC could come equipped with Buick, Chevrolet, Oldsmobile and Pontiac V8 engines As the mounting bolt pattern of the SM420 transmission is shared by many transmissions I would think that there are many non GM engines that could have an SM420 transmission bolted up to them. Hope that helps.
