I had a '65 that had this problem. What I did was a 2-man operation. I person gets under the truck and bleeds the air out as you already did. Then with a large pry bar, push the clutch open by prying against the clutch linkage. I used to push with my legs since they're stronger. When the person underneath pushes the cluch open, the 2nd person in the cab just pushes down on the clutch pedal. This always did it for me.

good luck!