Very rare and sought after set of heads in very nice condition. aluminum heads made by Hotton Sullivan Engineering in Dearborn, Michigan. The history of who made these heads is what is really neat. Don Sullivan was one of the engineers that Henry Ford picked himself to be on the team that would developed the famous Ford Flathead. Well after sometime Andy Hotton and Don Sullivan got together and wanted to make speed equipment for the Ford Flathead. So in about 1948 they started making Hotton Sullivan aluminum heads for the Ford Flathead. These heads w made in Dearborn, Michigan and the shop was right on Michigan Ave. in downtown Dearborn http://www.thehotrodsofdearborn.com/sully/heads.html