In 85, you could have a Turbo 350-C, which has a lockup converter. There will be an electrical connector in the transmission case, and if you remove the pan, there will be a couple of wires connected to pressure switches on the valve body. With the torque converter removed, the input shaft will be hollow, with an O-ring near the front, and a steel check ball in the hollow shaft. It needs a vacuum switch connected to the ignition switch and manifold vacuum to supply voltage to the tranny under light throttle. When the governor pressure switch and the vacuum switch are in the closed position, the converter will lock in. If either speed or vacuum drops, the lockup clutch disconnects. Later model 350-C transmissions used the vehicle's engine control computer to apply the lockup clutch.
Jerry
