[ModelA29]

What I have found out and I'm still chasing info for my head. Don Ferguson was said to have bought the patterns from Slim Rutherford and cast some. Joe Gemsa borrowed them and cast some more. Some were cast with a square block section added to use the stock distributor location. Rutherford used the same head casting for both his OHvalve and OHcam heads. I've found a guy in SoCal that has some castings and both OHV and OHC setups. Don Ferguson's son is said to have the patterns for the head, intake and valve cover. I think the complete engine is one of the McKee heads - it's flat on the exhaust side.
Charlie Yapp of Secrets of Speed Society did an article several years ago and is working on an update.
As a side note the head is said to be not a great street head. Designed as a race head to operate at higher RPM it's big ports don't like poking around at 1,500 rpm.