If you replace the head gasket, replace the seals (pucks) as well plus the four O-rings ( Honda part # 91318-ME5-003). The F2/F3 models use indeed a different head gasket than all the other CB750 Fours. The oil orifice is really hard to find. You might have to buy a shot head from a salvage store just to retrieve them. So, hopefully, Mike can help you out.