What should my timing be set at to stop pinging at wot

Rather than Octane Boosters I have had good success with a similar build on my 70 442 using VP110. 10% VP to the tank allows me to run alot of advance which the Olds 455 motor likes and also gives me lead for non-hardened valve seats. Octane boosters never seemed to do what was advertised. Real fuel did.