The Chappy has a very tired Ninco NC-1 motor, it was the only one we had available at the time of building the car, so on the faster tracks it is in trouble.
But we managed to find a set of the original grey-dust Ortmanns for the rear end, and that is the real secret I think.
I printed Doug's fabulous photos of our two cars and have them on display with a painting Adrienne made for me for a birthday a few years back:

She loves painting cars,either as subjects like this, or even painting clear bodies for my 1/24 retro racing cars.