1974 NASCAR International Stock Car Racing Rule Book Modified Division Section 20C-5 -- Carburetion

a. Only one single 3 or 4 barrel carburetor permitted. Multiple carburetion permitted on small block engines. No fuel injectors or superchargers or Holley 4500 Series carburetors and no inline carburetors permitted.

b. Carburetor restrictor must be used when required by NASCAR.