1974 NASCAR International Stock Car Racing Rule Book Modified Division Section 20C-27 -- Wheels - Tires

a. Any NASCAR-approved wheel or tire allowed, except that rim width shall not exceed a maximum of 15 inches and tires shall not exceed maximum sidewall measurement of 17.60 inches plus .15 tolerance at 38 pounds pressure mounted on 15 inch rim. No racing slicks, knobs or worn-out tires allowed. No cross grooving allowed. No smooth tires permitted at start of any event.

b. All cars qualified for any Modified race must start the race on the same make of tires used for qualifying. When make of tires is changed during a race, all four tires must be changed during one pit stop.

c. Should identification numbers, or serial numbers be defaced on any tire, the tire will be ruled ineligible for competition. It is the responsibility of the competitor to be sure the tire is an approved tire.

Explanation of Qualifying Tire Rule:

When an official detects a change in the brand of tires before the start of the event, the competitor will be allowed to change the tires back to the original brand used in qualification and car will be permitted to start event from rear of the field. If car starts on another brand of tires and is detected before payoff, car in violation will be disqualified.

d. Only NASCAR approved steel wheels permitted.

e. Wheels must be in excellent condition and free of rust.

f. Wheels that are not approved by Technical Inspectors will be confiscated and will become the property of NASCAR.

NOTE: When Modified competition is held on Super-Speedways and Road Courses competitors may use a front wheel setup permitting wheels that are narrow in width but both front wheels must be the same size as to actual measurements. Minimum wheel rim width shall be no less than 8 1/2 inches.