I have heard of this problem before with another customer, who was convinced I had supplied him with the wrong parts

.
From what I understand, the AP clutch has a lot more material on the drive plates than the original items, so it will not tolerate a stretched cable in any way shape or form. Also the ratchet has to be working exactly and be perfectly aligned.
After fiddling around with the cable and the ratchet, they eventually got the clutch to work, albeit with the clutch operating with only ½" travel from the floor. However, after a few months of use, the pedal travel increased nicely as the drive plate wore down and is now where it would normally be

.
Obviously this is typical of these type of clutches and is why I always recommend hydraulic actutation. However, you could always try one of these instead if hydraulic is too expensive

:
https://passionford.com/forum/showth...ht=new+product