Well then here's my best guess. It's a 416-8A missing the cover and mounted on the newer style frame and coned with the 211844 meant for the 416-8B and 426-8C. I suppose it's not a Z model since it's not stamped and the other models had the model numbers on the cover, and all the Zs I've seen pics of have the older style frame.

I could as Old Guy suggest pull the cover on the 8B to compare but you just about have to custom bend a wrench to reach into the spider to remove the bolts.

I have until this winter to decide what to do here when I do a complete rebuild on this pair. In the meantime I have my super minty and recapped 1982 19s with 416-8C and 902s to play with.

If anyone has more to add, please throw it out there.