When I originally built the truck I switched from the granny 4 speed to a 350/350 automatic. Later I switched back to a passenger car 4 speed manual. I fabricated a larger firewall plate for support and mounted a Wilwood 3/4" master cylinder directly in front of the original clutch operating arm, which is to the right of the brake pedal on the far end of the pivot shaft. The arm is connected to the master cylinder with a heim joint, steel spacers and a grade 8 bolt. I attached the bolt with double nuts to allow tension adjustment and lock in place. By retaining operation of the stock actuating lever, the pedal leverage ratio remains unchanged.
I've included a couple of photos to clarify the installation and shape of the firewall plate.
The Wilwood master cylinder can be seen here:
http://www.summitracing.com/parts/WIL-260-1304/
Hydraulic clutch systems are normally designed with a 1 to 1 ratio between the master and slave cylinders (both are the same size). Quite by accident I used a ¾” master cylinder connected to a 7/8” slave cylinder. This decreases pedal pressure at the expense of travel, in effect providing a “power” clutch. This arrangement releases completely, so I’ve never bothered to correct it. If I were to change the slave cylinder to ¾”, I could lower the pedal closer to the floor for convenience, but this would also increase pedal pressure. Since it works perfectly I’m leaving it as is as I prefer the easier clutch operation.
For the slave cylinder I purchased a Novak kit designed to install a Chevy V8 in a Jeep. I believe they have changed the kit somewhat, but here’s what mine looks like:
And here’s a link to their site:
http://www.novak-adapt.com/catalog/kit_hcrc.htm
CaptainFab also makes a nice setup similar to the Master Power Brakes arrangement that mounts the master cylinder on the outboard side of the brake booster. The CaptFab design corrects the pedal ratio issue inside the truck.