ping at high speed or foot to the floor

Your vacuum advance should not being adding advance at idle or WOT, it should only add timing under steady state light load crusing and 49 degrees under those conditions is not too much. If it is adding timing at idle then you have it connected to the wrong port. It should be connected to the "timed port" on the carb.

Typically if you have to much or to much to soon you will get the pinging at steady state part throttle or just as you get on the gas from a steady state condition but the pinging will stop as your manifold vacuum drops close to zero at WOT. If disconnecting the vacuum advance cures the problem then adjusting the preload in the pot is the thing to do. However, if it's still there with the vacuum advance disconnected then the mechanical advance is coming in to fast and you need stiffer springs.

If you are getting pinging at WOT then you have to much timing and/or compression for the fuel being used.