I had a friend curve my HEI for me and he didn't do it correctly. He gave me way too much advance. Right after we installed the curved HEI, we took it for a quick ride and he listened for pinging and there wasn't any so he thought it was fine. In the days following, I noticed a bad jerking of the car when going around 40-50mph at low throttle. Someone said this was a sign of too much advance. I removed the vacuum advance and sure enough the problem went away. Was my car pinging and I just couldn't hear it? I still think the advance is too far even w/out the vacuum connected. Could I maybe hurting my engine now and not knowing it. Why did my car never ping?

You might have had too much vacuum advance. Check to see where you are. I don't think that you were detonating, just so far past mst that your combustion was erratic.

In my experience surging and bucking are generally due to a lean condition rather than spark, but looking at the vacuum advance sounds like a good bet in your case.

Don't know how noisy your car is, but generally I would say that you could hear it at part throttle before detonation does damage - especially at part throttle.

Mike