They are all stepless except for the FWD engines

* Datsun B10 uses 160mm clutch disc
* all other A engines uses 180mm disc

B110 disc service spec thickness is 6.7 to 8.0 mm


If the clutch slips, resurface the flywheel + new disc + new cover. If the used disc is still thick enough, and the cover still measure out enough pounds, then there is oil/glazing damage done to the disc or to the flywheel -- which is why resurfacing the flyweel and using a new pressure plate cover is a fix-all, even if sometimes you can get by without resurfacing the flywheel


Btw, clutch cover of 320kg is for low-torque engines and results in very very light clutch pedal. Most only sell the A15-compatible 800kg cover these days. Which will work on A12 and other smaller engines - no slipping but requires more leg pressure