Mild 318 pinging

So you don't run vacuum advance at all? I've always been told that no vacuum advance will kill your mileage but I've never tried it myself. Of course, I know not everyone is concerned about fuel mileage when it's just their "toy" car. I didn't worry much about it when gas was in the 2's.
No vacuum advance at all. I get almost 20 on the highway if I drive it nice.