RBS stocks brand new straight cut steel gears for roots blowers. These gears fit 4-71 thru 16-71 superchargers. These are for .982" dia. blower rotor shafts that have or don't have the dead spline on them. The drive gear has the standard six bolt 5/16-24" bolt pattern with the 1.250" register on the gears. These are nice for timing the rotors without having to machine the gears.