When the engine block gets hurt it is typical to have to line bore the block and drop the crank down in the block making the racer use an undersize crank gear to get proper gear contact with the idler gear. This gear is made from billet heat treated 9310 steel and the bore has been precision honed and the teeth have been precision ground for perfect concentricity. The gear uses the industry standard two .187" keys a hundred and eighty degrees apart. The finish is black oxide. This gear will interchange with all Casale and most other gear drives such as Donovan, Indy, TFX and RCD.