RBS carries a full line of 5mm oil pump fuel pump drive sprockets. These are made from billet alum. and the drive sprocket uses a 1.00" bore with a .125" key and the driven sprocket uses the industry standard .625" shaft with a .187" key.
The driven sprocket also has four set screws to secure the pulley to the shaft. Select your cam speed (choose 27-33) drive with a 54 driven. Pulleys are designed to be used with 1.00" wide belt.
Racer can choose pulleys from drop down menu.