Specing Your New Clutch
The engineers at S.P.E.C. have helped put together a very user-friendly buyer's guide on their web site, along with detailed descriptions of their various stages of clutch design. In simple terms, if your engine is stock or near-stock, you can easily select the right clutch based on the data in the web site. If your engine is modified, or if you have questions on selecting the best unit for your usage, S.P.E.C. has a team of engineers available to walk you through the selection process in choosing the right unit for your needs, and they welcome the opportunity to discuss individual customers' needs.
For the record, they recommended their Stage 2 clutch kit for our C1 installation, and we couldn't be happier with the results. Engagement is smooth and secure, and pedal pressure actually seems lighter than stock, which they confirm with their test bench results. Plus, the unit they supplied us featured an optional aluminum pressure plate housing (with steel friction surface, of course), resulting in a saving of about 6 pounds of rotating mass. The result is quicker throttle response and faster engine spool-up.
Finally, as they say, reinstallation of the trans, shifter, and drive shaft is the reverse of disassembly. Two cautions: 1: When reinstalling the transmission be certain the input shaft engages the disc splines and also the pilot bushing; do not try to draw the transmission the last inch to the bell housing by tightening the trans bolts, and do not let the trans hang on the splines of the clutch disc. And 2: adjust the length of the threaded clutch fork push rod to achieve 1-2 inches of free play at the top of the pedal and clutch engagement at about one third of the way up. This will assure that the clutch fully disengages for shifting, and will also assure that the throwout bearing is not contacting the pressure plate fingers when the pedal is at the top of its travel.