[DougD]

The frames and rear ends between the alum CSX and Kirkhams are essentially identical. Fiberglass CSX cars have the same rear end, the same basic frame, with different small diameter tubing to attach the body.

Both manufacturers started out recreating the original cars with great accuracy. Through the years, both have begun to diverge from the '60s cars in terms of suspension, brakes, wiring, gauges, and other details.