Shimming the pivot ball helps only if they are worn out badly. Other than that it just pushes the slave piston up its bore even further and makes the throwout bearing ride the pp fingers with more pressure at all times. It doesn't matter how much shim you add after a certain point, it won't change the amount of throw you have at the slave one bit. It won't even give you the extra throw you need for a thicker disk either.

A little shim, i.e. 1mm is good on a new ball and fork for future wear and tear. I tend to do the same as Giz mention above.

On the other hand, I did mention the disk is 20 thou thicker than an ACT disk, uncompressed. ACT PP are designed to be used with ACT disks, which have a flattened out marcel. Uncompressed thickness is what affects the engagement point.

I've already been through this BS with the southbend disk. The disk is soo thick it throws off the pivot angle on the ACT pp fingers. This is why it feels like it will work. With the car off the pressure feels good in the pedal, but still only disengages at the end of its throw !

I actually took my ACT flywheel, ACT 2900pp and southbend disk, bolted them all up and put them in my press to simulate a clutch system. I took the measurements and came up with my conclusions.

You may have noticed that the pp fingers were almost flat with the disk bolted up. I almost tossed the damn thing like a frisby. If you like your clutch engaging off the floor and killing syncros up top, keep using it with the ACT pp as is!

Changing the master/slave and pivot ball/fork may help a little, but its not gonna bring your clutch pedal engagement height back to like 3/4 of the way up. Try them out, if no difference, post back and I'll tell you what the solution is

I'm glad I actually do my own fine analysis of aftermarket parts that I install on my car instead of just blindly following the hype!

Good luck with getting it to work, some guys love it some don't