Adjusting dizzy timing....?

[Sy Hollinshead]

Just a quicky. My Econoline is running well, but under load i can hear it pinging. Which way do i need to turn the dizzy to get rid of this normally....?
Sy

 

[JackFish]

Clockwise will retard the timing.

It might be pinging now due to carbon accumulating on the top of the pistons which increases the compression ratio. You might try a higher octane gas.