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.
In 1981, Yenko made his last modification of which only 19 were produced, the Turbo Z Camaro, and only 5 are known to still exist. He added a turbocharger to 350 engine. He sold the Yenko Chevrolet dealership in 1982, which had been family owned since 1934.