[buwalda]

Engine temp affects pinging. Higher temps= more probality of pinging. You should do everything you can to get the engine temp & air inlet temp as cool as possible. If you can reduce temps, you may not have to reduce total timing, the rate of timing, or use octane boosters.
Use a 160 high flow stat. Make sure your impeller clearance is minimal, as outlined in the 'heating & cooling' section; make sure your fan is working efficiently & that your radiator is not partially clogged. Blocking the exhause crossover in the intake will help a little, as will a cold air intake to the carb, but engine warm up will take a little longer in winter.