Trouble Installing 18 spline A-833 through dual disc clutch assy.
Be advised that Quicktime bellshousings have issues. I would check the transmission register runout vs. crankshaft and make sure it is true to the block. The height of the clutch fork bracket is also incprrect. Lastly, keep and eye on the bell crank bracket. They are thin and tend to fold up over time.
If everything is lined up to the crank centerline that leaves disc alignment as your culprit.