What is your initial advance set at?
I suggest that you start out by setting your octane selector at the center position mark and tighten up the 1/2" hex head bolt, then set your timing by loosening the clamp screw which is behind the distributor to 5 degrees BTD (On the BB) as a starting point.
Once you have established this factory spec, drive it up a steep incline and listen for pinging.
Pinging (detonation) is usually from too much timing. It can come from too much initial timing.
The beauty of having the octane selector is that once you establish the factory setting for the timing, you can make adjustments on the side of the road without worrying about going back to the factory setting without a timing light. Just loosen the octane selector bolt and return it to the middle mark.
Sorry it took me so long to respond to your question, had other things going on and this was put on the back burner. I verified with a timing light the initial advance is indeed set to 5 degrees with the octane selector at "0". If I set the octane selector indicator in the "retard" range, idle quality suffers a little but I still get pinging at heavy throttle around 1800 rpm. No pinging with less throttle or higher RPM. So, to me, it's acting like the mechanical advance is just coming in too soon and needs to be delayed.
