well mate i think if DaddyRacer see's this post he could steer you in right direction, but i'd say 95 octain would be safe, just it's all unlead, the ol ironhead is cast iron so cast iron valve seat. i guess eventually the seat will go runing unlead. but not to worry as can get hardened valve seat inserts. but while she's runing leave it.

what state are you in mate?