Tap and die sets include a gauge that calculates threads per inch. Select the corresponding die that matches with the reading on the thread per inch gauge, and set the die in the handle that comes with the set.
The IROC-Z model of the Chevrolet Camaro first made its public appearance in 1985 as an add on option to the 1985 Camaro Z28 model. But its origin began long before that. IROC stands for International Race of Champions which is an automobile racing series similar to what NASCAR is.
The Chevrolet Camaro is  a sports coupe that has been manufactured since the 1960s. The RS designation has been used for a trim level or a model-year variant in each of the vehicle's generations. Rally Sport RS stands for Rally Sport, which originally was an appearance package available on the first- and second-generation Camaro.