833 Transmission won't disengage at stop after 100 miles.

ok, you need to check the disk, first. you need spin it between centers to make sure the hub is not bent and the disk runs true. The disks can be bent by someone installing the trans, and allowing the trans to "hang" on the splines before it is fully seated in the BH counterbore. Then bolt the pressure plate and disk back onto the flywheel and check that the fingers are even. I don't know what the tolerances are, offhand, but I would guess you wouldn't want more than 0.015" or 0.020" difference on the finger height. One of the fingers has been damaged, so you might want to fix that beforehand.
If that's your car, the 64 dart gt vert, please don't give up on the 4spd. The sl/6 is SO much more fun with a 4spd.