Chase Bays s product is perfect for those needing to upgrade to a Wilwood 0.625 (5 8) or 0.75 (3 4) Clutch Master Cylinder on FC3S FD3S chassis without modifying the firewall. Ideal for transmission swaps requiring a larger bore, this upgrade is necessary since no larger FC3S FD3S cylinder is available. It also looks much better and matches Chase Bays s Brake Booster Eliminator. You can choose between a Billet Chase Bays Reservoir or a Clutch Feed Adapter hose to share fluid with the brake reservoir, like the original Mazda setup. The black powder-coated plate is made from 0.125 (1 8 or 3.17mm) steel and comes with master cylinder mounting studs pressed and welded in, using the same M8x1.25 thread type as stock. Note that it doesn’t fit with a stock clutch line, but the Chase Bays Clutch Line with a Banjo connection works perfectly. Use the included Banjo Bolt when adding the Master Cylinder, as the thread pitch differs from the stock clutch MC to the Wilwood MC.