[5150coupe]

resolution: damper/harmonic balancer needs to be replaced. the rubber on the outside of the damper is coming loose and moved a little. i basically just ran the car at high rpm, pinged it, and moved the timing down. after several repeats the pinging stopped and i will leave it this way for now. but the long term fix is going to be to replace the damper. the adhesive on the damper will eventually fail and it is fairly common for the rubber outside to loosen on a high mileage motors. be aware that the damper should be replaced asap if this happens to you since you may damage the motor if the damper comes off completely while driving.