I'm also building/restoring old PARMA Womp-Womp chassis. Picking them up of eBay.
This was an old steel chassis that was really beat up. The wrinkle paint really brought the chassis back to life (looks wise). New bushings, gear, tires and a motor and we're off to the races.
The fun in running these types of chassis is that there are no traction magnets to help keep the car on the track. Very tail happy if so desired.
Bodies are in progress, 917 and a 917/30.