During production, a modification/upgrade was performed on the clutch linkage.
A pseudo-kidney-shaped "lever" was added to reduce pedal effort.
(Acutally, it reduces pedal effort at the top, for pedal effort at the bottom, where you have more leg leverage and don't notice it.)
I pulled what is necessary out of a scrapped car in order to have a machinist review it for possible manufacture.
There is a diagram of the full linkage, and a photo or two in my Master Brake upgrade article at:
http://geocities.com/provamo72/ Next to a centerforce clutch, I doubt there is anything else that works as well to reduce the effort.
Chuck