first thing to do is to check the timing and see where it advances to total at 3-4000 rpm(what ever rpm it stops advancing at)
It should be less than 40 and probably you will have to back it down to 35-36 before you get rid of the ping--when you get it backed down enough that the ping is gone, check it to see where it is at at the higher rpm and also at idle rpm--you may have to recurve the advance in the distributor so it won't be lazy off the bottom rpm