I have used a stock replacement diaphram style clutch for a J20 with a 401 that has a diameter of 10.94". This is sometimes called a "scalloped" clutch as it has the same bolt pattern as the original 10 1/2" stock clutch and is scalloped out around the bolt holes. A regular 11" clutch usually won't fit the stock flywheel as the pattern is larger. By using this clutch, you gain alot of surface area, for a better hold and longer life, that the stock clutch. It usually won't cost much more than the stock one and the pedal effort is light. I'd recommend using new parts rather than rebuilt. Centerforce clutches are expensive and unnecessary and hard to get warranteed if there is a problem, in my experience, and the "Dual friction" disc wears out the cover quickly. Hope this helps, good luck.
P.S: Check for interferance with the bellhousing with the large clutch before bolting on the trans, T-5 bellhousings have a small rib inside along the bottom that needs to be removed for clearance. The earlier housings should be the same as the 401s.
P.S: Check for interferance with the bellhousing with the large clutch before bolting on the trans, T-5 bellhousings have a small rib inside along the bottom that needs to be removed for clearance. The earlier housings should be the same as the 401s.
