Clutch won't disengage

We ran into a mystery while replacing the clutch assembly on Leftcoast65's van. Now, when you push the clutch pedal to the floor, the clutch is not fully disengaged. Grinding gears. The new throwout bearing was longer than the one we took out.

Discussion going on here:

https://vintage-vans.forumotion.com/t39210p225-dons-day#215705

Thanks.