[Cliff R]

I don't understand the need to mess with the distributor right to start with.

Before making any changes to it I would have taken it apart here, cleaned out the old grease, cleaned up the shaft on the lathe and the advance mechanism. Check the housing for wear at the bushings, replace the rubber sleeve on the advance pin with a stainless steel one, put all the stock parts back on it, new grease, then check to see how much timing it is adding.

I would NOT have used any type of aftermarket advance "kit" and simply started with the stock parts.

Using my degree wheel I'd check to see how much mechanical advance is in the curve before placing it in service. At that point if I wanted to shorten up the curve some it would have been done using the MIG to shorten up the slot the advance pin moves in.

Using precision drill bits I'd measure how much timing the VA was adding, and modify it if/as needed with the MIG.

I will not under any circumstances use any of the aftermarket spring/weight kits or the "adjustable" vacuum advance units. I've found much better results with modified stock VA units and stock distributor weights and springs. I also don't understand the want or need to put a lot of initial timing or all-in timing curve into a distributor headed for a high compression engine on pump gas. That in itself is a recipe for disaster and the best way I know of to put pistons and rod bearings into the oil pan.

What puzzles me in your case is ping or detonation during a no-load test. Are you sure you don't have somthing in the exhaust system leaking, or a pipe or muffler rubbing on something producing a metalic sound during your test?......