1974 NASCAR International Stock Car Racing Rule Book Grand American Cars Section 20A-2 -- Engine

a. Displacement -- 305 cubic inches maximum. (OVERBORING: A total maximum of one cubic inch overbore will be permitted for cylinder wear). Engine displacement may be increased or decreased provided the displacement does not exceed the maximum 305 cubic inches displacement. An engine must be an advertised option for the model in which it was approved.

b. Carburetor(s) -- Maximum one four-barrel. Only 1 11/16 throttle bore. Holley 4500 Series carburetor not eligible. The approval of any carburetor shall mean approval for all competitors and cost of carburetor shall be a factor of consideration for approval.

NOTE: For AeroWarriors.com users, Grand American Cars are governed by the same rules as the NASCAR Grand National Championship Division, with the exception of this Section, and the following:
Section 20A-1 -- Competing Models
Section 20A-3 -- Engine Mounts
Section 20A-4 -- Minimum Weight
Section 20A-5 -- Frames
Section 20A-6 -- Ground Clearance
Section 20A-7 -- Wheels