1999 5.2/46re into 1974 Duster?

Sounds like a sweet set up. I will be useing a 518 with a one wire hook up for over drive. Wish I had everything to put a 4L80 in the car. But I dont

The shifter controls the transmission to go into overdrive by putting it in 4th gear. The one wire hook-up on my set-up controls the lock-up clutch in the torque converter.