Any of the general versions of center lock wing nuts (a.k.a. knock offs) Ted Halibrand’s company supplied to Shelby American could be used on any ‘pin drive’ race wheel providing that the machining of wheels and nuts mated properly (specifications varied year to year and car to car and wheel type to wheel type).
The first nut design was adopted from other earlier racing cars and was made of cast steel. They were used in all types of racing including ‘FIA’ events and drag racing. Being cast steel they were somewhat fragile and were often broken, usually during removal.
Shelby American wise these were replaced by a new much stronger forged aluminum design. Harvey AluminumŽ forged the blanks and Halibrand machined them to suit various Shelby cars as well as many other types of race and street cars and specific wheel combinations.
Shelby American wise the strongest were the final cadmium plated forged steel versions; also machined to fit various Shelby race and street cars and specific wheel combinations.
1964-65 pictures of SA team cars show both forged aluminum and forged steel in use. Note that on the forged steel parts "HALIBRAND ENG. CO." text runs clockwise and "TORRANCE CAL" runs counter clockwise around the center.