So ....?
 

Well, I have have the same problem with my clutch not disengaging all the way like several people here. I have not seen a solution yet, what are we gonna do?

Same clutch I have had for a few years now.
Thought it was hydraulics, bought a prebled GM setup, no change.
Pulled the trans and carefully inspected everything before putting it back together, no change.

Pulled off slave spacer and bolted slave on. Slave is now 1.25" away from bellhousing instead of 2" with the spacer on. This seemed to work. This is no solution though, I want to know the real problem.

Disc is not on backwards
Throwout looks like new
Flywheel/PP look like new
Clutch fork certainly doesn't look bent, not sure you could bend that stout piece.
Clutch fork is tightened down good
Pilot bearing in good shape

Did the crankshaft move? if it did, it seems the it would certainly affect the way the car runs?

SO WTF?

You mention removing a "spacer" that appeared to be about 3/4" thick (2.0" - 1.25"). It's been a while since I swapped out my T56, but there was a "cup" type extension, maybe 2" long, that the slave bolted to. Do you have something different than that?

I was referring to the cup type extension Fred.

The bellhousing has 2 studs coming out of it that the 2" thick cup/spacer slides over, then the slave is held onto the protruding studs by 2 nuts.

I removed the spacer and just slid the slave over the ends of the studs and tightened the 2 nuts down about halfway because the studs are only threaded about halfway down.

I cranked those nuts down to nearly the ends of the available threads and started the car on jackstands, no dice.

In a last ditch effort, I got under there and cranked just a little more and tried again. It worked, full disengagement.

I them measured how far the slave face was away from the bellhousing and it was 1.25", a full .75" closer than it ever needed to be before. All clutch components are the same pieces I have been using for years and it always worked with the factory 2" spacer in place before.