They came in some Chevy IIs. I wouldn't want one in a car heaver than that but a little '62 two door post with a built 4 cylinder would be fun. Probably not much savings in the build but different. Start with a 181 Mercruiser and you are already at 140 HP.
So something under 2800 lbs. Not even the early '70 to '74 2nd gens fall into that range. The early 3rd gen Camaros had a 4cyl option, but I'm not sure what engine that was, but I know they were lighter than the later 2nd gen Camaros.
