For the most part, dual-disc clutches have been relegated to the racetrack and do not behave on the street since they usually act as more of an on/off switch for the clutch without the finesse most people want/need on the street. Well, McLeod came up with some new clutch facing material that'll hold much more horsepower than previous designs and only requires light effort to engage the pedal-it's like the best of both worlds!
McLeod's Street Twin clutches come in two stages, the RST and the RXT. The main difference between the two is the clutch facing material. The RST uses an organic facing on each side of its two discs and is rated up to a whopping 800 horsepower, and the RXT has a metallic facing rated over 1,000 horsepower, and remember, these are good for street use, which is unheard of! Another reason they hold up to these ratings is that the clutch discs are 9 11/16 inches in diameter, which is smaller than the stock clutch, but there's over twice the clutch surface area working for you because there are two clutch discs. They are also lightweight, which reduces reciprocating weight and gives the clutch a low moment of inertia that doesn't require as much horsepower to spin.
 Depending on where you mount...  Depending on where you mount your master, you may need to reinforce the area due to the amount of force it takes to push in the clutch pedal. The firewall on the F-100 was braced around the brake master for this reason, but there wasn't anything but sheetmetal where I mounted the clutch master. So I marked the general size and shape of the doubler plate that I'll weld to the firewall for strength. |  First, making sure the truck...  First, making sure the truck sat level side to side and at ride height, I leveled the master before marking and drilling its mounting holes. |  I mounted this trick master...  I mounted this trick master cylinder from CPP that I'll be using to double-check that nothing will interfere between the two masters before getting too far, and there seemed to be no issues. If you are using power brakes, be sure to include your power booster in the mock-up. I'll explain more about CPP's master cylinder when I plumb the truck. |
 I cut this out of 1/8-inch...  I cut this out of 1/8-inch cold-rolled steel and sprayed Dykem layout fluid on the backside to trace the holes for the clutch master cylinder. If you don't have Dykem, spray paint will work too-just clean it off before welding. |  Making the firewall thicker...  Making the firewall thicker was only part of the battle. I also made this vertical gusset similar to the ones on the brake master cylinder's extra support and used a holesaw to put the 1-inch hole in the top for wiring to pass through. To avoid putting too much heat from welding into the firewall, I TIG welded the gusset to the doubler plate while it was off the truck with my trusty Miller Dynasty 200 TIG welder. |  The bolts that mount the clutch...  The bolts that mount the clutch master to the firewall are perfect to hold the doubler tight to the firewall while welding the two together. I welded the top of the gusset to the underside of the cowl that hangs over the firewall, and to the left I welded the doubler plate to the brake master's extra support bracket. It's amazing how much this helped stiffen the area! |
 A bracket needed to be built...  A bracket needed to be built off the clutch pedal to connect the pushrod from the clutch master to it. I built this from the same 1/8-inch cold-rolled steel I used earlier. When mocking up the bracket, make sure the pushrod is level and not hanging down so it'll push straight into the clutch master cylinder. |  Because the pushrod is lower...  Because the pushrod is lower on the clutch pedal than where the pedal would travel 1 inch once it hit its stop, I had to modify the pedal's stop to prevent the pushrod from traveling too much. With the straightedge ruler, I measured the center of the cross-bolt in the clevis on the end of the pushrod in its relaxed position, then pushed on the pedal until the center of the bolt traveled 1 inch. This is where I need to make the pedal stop. |  Next, we need to connect the...  Next, we need to connect the clutch master cylinder to the clutch pedal, which gets tricky due to the cramped space under the dash. The ideal spot for the clutch master's pushrod is the vertical position on the clutch pedal where the pedal travels 1 inch once it reaches full travel, otherwise known as the floor. This can be measured with a level straightedge ruler from the firewall to the face of the pedal. Obviously, the pedal travels less the closer you get to its pivot point, so before starting any of this, make sure you mount the clutch master within this area and no more than 3 inches from the pedal's pivot point. In a perfect world, it would be nice to have the pushrod come through the firewall and meet right up with the pedal, but there wound up being about 3 inches of side-to-side distance between the two. |