I had a similar issue before, it was with a clutch that was in my car before I bought it, the disk material itself was acutally much thicker causing the fingers to go so far in with my ACT XT pressure plate that there was no way it was going to disengage. What type of disk is it that you are using? What kind of step did the machine shop put on your flywheel? I dont know what stock step is, but sometimes machine shops put more than stock step to make clutch 'stronger' but it makes it so you can't disengage, like in this instance.