I've been doing some thinking about that piston Steve, especially with the highly eroded top part. We seldom ever had that happen to a piston, and I had been puzzled by it earlier. Didn't the FA Konig's have the same size piston? If so, I'm thinking this might have come from the summer of 1969 in which we were experimenting with nitro prior to the NOA North South Championships. We had such piston erosion after we had increased the head volume, but before we got the timing down right. The A motor is the only one we played around with adding nitro to the fuel.