Reply to "Delay Mechanical Ignition advance"

It could be a vacuum leek, make sure all your carburetor vacuum ports are plugged and all your intake ports are not leaking. Without knowing your compression ratio,or if you have steel or aluminum heads, pinging at low R.P.M. that goes away as you accelerate (add more fuel and stopping the early cylinder detonation by enriching the mixture )is classic vacuum leek systems failure, leading me to think your air to fuel mixture is the problem. When you set the distributor up, disconnect the vacuum advance.
It is very hard to see some vacuum ports as they are burred under the carburetor or behind the intake, so get the mirror out and make sure you have no leeks. I had a vacuum plug fall off installing a carburetor, it caused a pinging that drove me nuts till I saw the open port under the front of my carburetor through the back window.