1966 NASCAR International Rule Book Specifications NASCAR Grand National Championship Circuit Section 20-17 -- Carburetor

a. Carburetor must be available production model in manufacturer's line. No external alterations permitted.

b. Cars are limited to one four-barrel carburetor not to exceed 1 11/16 inch throttle bore and with all four barrels functioning.

c. Jets may be any size.

d. Wedges permitted.

e. Heat risers may be blocked.

f. Any NASCAR approved gasoline filters may be used. This applies to all late model divisions as well as speed trial and record attempts.