pinging

[Gorf]

The 500 in my 75 Hearse is pinging quite a bit at partial throttle. It seems to go away if I really tromp on it. And it especially does it if it starts to get hot, like when sitting in traffic and stuff. I was suspecting that maybe the carb is tuned a bit lean at partial throttle. But head temperature now has me thinking. My timing is set to about 6 degrees. Any thoughts?

[DOC]

Gorf,
If you will run the stock EGR valve with the correct vacuum port on the carb (also through the factory TVS) it will not ping. The main purpose of the EGR valve is to reduce combustion chamber temp, bringing the volume of Oxides of Nitrogen down. The factory carb is calibrated to compensate the fuel mixture. Try it. It works.

DOC