There is a fine line between too little (or retarded) initial timing at the crank (which may cause overheating) or too much timing (which may cause detonation). The best plan, in my opinion, would be to use the best possible fuel and time the motor by ear.
Loosen the distributor clamp bolt just enough so that the distributor will remain where you put it, but you can turn the distributor by grasping the distributor cap with both hands and turning it slightly one way or the other. If the motor pings, turn the cap counter-clockwise a little and drive again. If there is no audible ping, turn the cap clockwise and drive again. Keep doing this until you have found the best advanced position for power, but there is no, REPEAT, NO audible ping at any engine rpm's. When you have found that position, turn the cap another fraction of an inch counter-clockwise to insure there will be no pinging. That will be the best position for the initial ignition timing. Again, BEST POSSIBLE FUEL.
1971 was the last year of high compression motors in the Ford lineup. A permanent cure would be lowering the compression ratio with dished pistons or heads with larger combustion chambers. DO NOT USE THICKER HEAD GASKETS TO LOWER COMPRESSION RATIO, IT WILL MAKE THE PINGING WORSE.