Are these cast iron or aluminium ? Yes I agree they're diamond or diamond-elkins. They look very similar to the heads Glidden ran in about 1980. The valve cover bolt hole is no problem w/ stud & loctite or epoxy. Unless they have cracks they're great w-2s. A flow bench test would be interesting. They're the early style of casting. An indy intake can easly be modified to bolt up if you are happy with a single carb. They could have an intresting history. Make'em work and haul ass !