727 no forward or reverse

Just finished swapping in a 383 in my car. Got a "rebuilt" 727 at a swap in in Daytona at thanksgiving.

Got the motor broke in and running great. Put about 5-6 qt in prior to 1st fire. Checked level in neutral and got level up on dipstick. Tried to back the car out of the garage, had to rev the motor to get the car to go. Put a little more fluid in and started to move more freely.

Went for a drive up the street had to rev motor in drive to get going. Motor would rev and slowly rol and Then take off quickly

Did this same test over two days. Tonight I go into the garage and warm the car up. Go to test adjustment. I take tension off and on the kickdiwn cable.

Now the car will not engage any gear. Have about 1/4" mile on the trans.

Any thoughts? Or suggestions?