Chase Bays s clutch master cylinder upgrade is perfect for S chassis owners needing to upgrade to a Wilwood 0.625 (5 8) or 0.75 (3 4) bore without cutting or drilling the firewall. Essential for certain transmission swaps, this upgrade offers a larger bore clutch master cylinder solution unavailable from Nissan. It also enhances the look, especially if paired with the Chase Bays Brake Booster Eliminator. The kit includes options for either a dedicated reservoir or a clutch feed adapter hose to share fluid with the brake reservoir, an aesthetic and functional improvement inspired by BMW and Mazda setups. For those using the Brake Booster Eliminator, an additional add-on simplifies the setup further. The package comes with a -6AN hose and fittings to adapt the brake reservoir to the clutch master cylinder using Wilwood s hose adapter, as shown in the installed photos. Note, it doesn t fit with a stock clutch line, but the Chase Bays Clutch Line, with its Banjo connection, works perfectly. Ensure to use the included Banjo Bolt since the thread pitch differs between the stock and Wilwood MC. The mounting plate, made of 0.125 (3.17mm) steel, features pressed and welded studs. Attach it securely to the clutch pedal s studs through the firewall and tighten it to the master cylinder before installation, as the upper nut is inaccessible once installed due to the firewall lip. This upgrade not only enhances performance but also integrates seamlessly into the S13, S14, and S15 models.