1966 NASCAR International Rule Book Specifications NASCAR Grand National Championship Circuit Section 20-3 -- Brakes and Hub Assembly

a. Any interchangeable brake and drum assembly may be used. No spot or disk brakes allowed unless optional equipment on a production model of a manufacturer's line. Dual master brake cylinders are recommended.

Wheel treads must conform to approved specifications for make and model.

b. Backing plates and drums may be drilled for better air circulation. Scoops may be used for brake cooling, but all scoops must be approved by scrutineer in charge. Fans, blowers or other attachments will not be permitted.