Sorry I didn't see this thread before, I could have likely saved you a lot if time and grief. It is the length of the pivot ball in the bellhousing (that the fork sits on). You need the ball on the attached link. As mentioned, you can also get a thicker release bearing to correct this but I prefer the adjustable pivot ball.
Follow measurement instructions, cut to length, and install. All adjustability and alignment will come back into play.
Also, as a side note, always install a simple spring from the fork to the clutch linkage (runs generally parallel to the clutch adjustment rod you will notice little holes drilled in the end of the fork and on the linkage for this) and a return spring from clutch pedal to the dash.
Just ask me how I know....
http://www.summitracing.com/parts/mcl-16908