Show me your 340 ignition wiring looms/routing

Nice. Some people say its a retard adjustment but if you center it I would call it a timing adjustment. For example if I ran pump gass vs racinng fuel. Would you agree based on your experience? My application would be actually summer heat in AZ vs winter. We run the cars here all year long and there could be as much as an 80 degree swing in the valley depending on time of year. So hot preignition is an isdue. I would love to use it for ping control

Yes you can center it according to the instructions. You can run it as a timing adjustment. It would work great for what you want.

Fred B