cylinder head id

What all else do you need to know? They predated the 915/906 heads, 2.08/1.60 (not 1.65 unless you measured them and someone before you put them there), have earlier style, less desirable intake runners...you can put the same size valves in them that you can with any other BBM head. They'll work on any of the engines plus 440s as listed above...they do not have hardened seats.

According to the little bit of literature I've read on them, the chambers were supposed to be around 75cc, but typically measure out closer to or over 80cc, intake and exhaust runners, I don't have info for--but I bet there's a member on here that does. If you haven't figured out how to use the search function yet, search in here for "516 heads"

They're good for a basic rebuild if you have no other option, but for power production pretty much any other later model head will provide better performance capacity. I hope that's a little more helpful