Found This Interesting Page On The Hamtramck Registry

Iron heads ported by Ron's in the US..titanium valves,retainers and locks.some of the very first sheet alum intakes.C M/P index 9.00 to 9.99 most could run under the index.

but what "iron heads" and what did they flow?

they would have to flow well over 350cfm to take a motor over 8k.