Has anyone on here changed the timing chains on a dohc 4.6? My 57 ford fairlane 2d ht blew a head gasket and in the process of removing heads and cams came across an unusual situation. The cams intake and exhaust have keyways on the front end. The secondary chain sprockets also have keyways. But there are no keys present in the keyways. When you remove the main cam chain( which has a key made into it) and bolts are loose, both sprockets and chains rotate freely on the cams. Cams are held by aftermarket holder at rear of cams and in the center of camshaft. Why no key?