[Dwight Southerland]

1966 rule book states ""Headers are also accepted, but exhaust must be routed through mufflers and tailpipes. All mufflers must be productions type and installed in the stock location with tailpipes extending at least to the rear axle. The main body of any replacement muffler must be at least 18 inches in length." When I built my first race car and constructed the legal system, I was told by Chuck Nelson in a letter that the exhaust pipe had to be a minimum of 1 1/2" and the muffler must be at least 3 1/2" in diameter. That was not in the rule book, but was one of those "undocumented" specs.