1968 NASCAR International Stock Car Racing Rule Book NASCAR Grand National Championship Circuit Section 20-16 -- Clutch and Flywheel

a. High speed clutch assembly permitted as long as flywheel weight is not changed.

b. Size, weights and material must be normal customer production only.

c. A steel scattershield, not less than 3/8 inch thick, must be installed over flywheel and clutch area. Special construction all-steel clutch housings are permitted in lieu of separate scattershield. "Clutch-Flywheel Flexible Housing Safety Shield" is approved for use.