Multi-disc clutches
 

Today, there is a lot of talk about the great leap foward in clutch design that dual disc clutches are. It should be know that the original racing GT-40's used TRIPLE DISC AP Racing clutches. These clutches were the standard in the mid-60's to the early 70's, not only for the GTFords but for the Porsche 917's etc. They were about 7 1/4 inches in diameter and about 2 inches thick. They were really light and with a light flywheel were great for getting that RPM up fast. As I recall, it weighed comlpete, flywheel and clutch about 14.5 lbs. This was a steel flywheel and no aluminum anywhere. There were two major problems with these clutches. First they cost about $800-$900. That's like 8-9 thousand dollars today. The other problem was a major one. The clutch was either IN or OUT. You could not slip them at all. The joke, when you tried to use one on the street was, it was good for one traffic light and then it was gone. I used one on a car I used for the street. It didn't last very long. Not wanting to spend the money for a new one, I took it to a clutch and brake refacing shop I worked with, to see if they could help. I asked them to see about refacing the discs. They told me that a VW clutch disc material as a replacement would work fine. They stripped the discs and bonded on the VW faces. With more than 10,000 street miles on that clutch it was still working fine when I sold that car. So, the point is not everything we think is new is new and when you order a new clutch research the material as it makes all the difference in the world as to its performance.
Multi-dics clutches in my opinion are still the best for street or racing.

Bill K