[SoTxButler]

Interesting question. I spoke with Ron Butler and his explanation is that the tires were rubbing badly on the fenders and they were using anything they could to flare the fenders to clear the tires. He said most of those flares, which were done while racing, were not very pretty and that it would be rare to find two fenders flared exactly alike. Ron says the first 50 bodies from AC had what you call narrow fenders and beginning with body #51, the fenders were 1" wider. They just split the fender and added 1" in the middle.

So, depending on which body number you look at, there are both narrow and wider fenders. I'm sure it gets complicated since the early CSX numbers may not (probably won't) correlate to the body number.

Personally, I had no idea how it happened, but that is Ron's account.