1966 NASCAR International Rule Book Specifications NASCAR Grand National Championship Circuit Section 20-8 -- Engine

a. See Rules 1-a and 1-d.

b. Numerals indicating the cubic inch displacement of engine must be painted on both sides of hood in numerals at least eight inches high.

c. Internal polishing, porting, altering and/or relieving of motor parts permitted.

d. Oversized oil pans and oil coolers are not to be used unless approved by NASCAR. Oil pans must have a minimum ground clearance of five inches.