Originally Posted by Harbone
Scoot your pinging might be carbon build up on the pistons, those old Mopars had a tendency to crud up. Does it have an EGR valve still on it? That will make them ping too when they are bad.
Get something turn burn that carbon off, ATF or SeaFoam nice and slow through the carb will take care of it, just make sure you are in an open area cause it will smoke like crazy!
Back in the day when anything that burned gas would get Carbon Build Up if it wasn't "Blown Out" periodically, we used . . WATER . . Bump the idle up to about 750 rpm, and verrrry slowly
trickle water down the carb. It'll stumble a little bit but just keep on keepin on for about 5 minutes, from one barrel of the carb to the other . . Make sure the engine is at operating temp before you start . .
Pure Old School . . .