Need a Mopar guru: 273 part-throttle ping driving me crazy!

That is the original 273 intake, so no EGR. The Holley is a replacement for the carter 2 barrel. Looks like a "LIST" R7890 number? If it pings with the vacuum advance disconnected, adjusting the advance will not matter. The 35 is just for initial and total timing, you can go past that with vacuum advance. I would not go lower than 0 for initial timing. Does it ping if you set initial at 0? What octane? The vacuum adjustment is to add or subtract washers, can't remember which off the top of my head, inside of the removable vacuum nipple. Is the 273 solid lifter or hydraulic? Can you remember?