Bullet Lines TC30 Torque Converter 5/8" Jackshaft Sprocket - This is a standard 30 series torque converter jackshaft sprocket with a 5/8" bore and 3/16" keyway. Our sprocket comes in a 12t for a #35 chain, or a 10t for a 40/41 chain. These 2 gear sizes are exactly the same in diameter, so ratios will not change between the 2 gears. Only thing that changes is the chain size. This sprocket will fit nearly all 30 series torque converter brands.