Hello From Oklahoma

My name is Jason and i run a repair shop down in Marlow, OK. I have a customers 74 Duster that i've been working on and I joined the forum because I almost have this thing done. (skip to the last paragraph for what i need help with) It has been a journey for sure. It came in for a complete wiring harness replacement, which we got from American Auto wire. I built up an all digital instrument cluster using Intellitronics gauges. Updated the entire AC system with a kit from Classic Auto Air. Everything has been time consuming. This car originally had a 318 and the owner who is a 74 year old lady brought it in because her husband did everything wrong and turned this car into a Frankenstein of parts. Nothing thus far has been stock. Nearly every wire had been spliced multiple times. What should have been a labor intensive but straight forward rewire has turned into a nightmare. I have worked all the problems out with alot of research and perseverance. I am down to wiring up the transmission and getting my bay back. What i am looking for is information to wire up the lock up converter and the neutral safety switch.
I am assuming that the neutral safety switch has gone bad. From what i read, the center pin is the ground feed for the starter relay. There is no continuity. It has 2 black wires and a brown tan wire on that harness. That i can work around.
The lockup has a pressure switch with 2 wires, one grounded to the transmission and the other to feed a ground signal to a relay to power the lockup solenoid. I have looked for quite a while and cannot find a similar transmission. All i need to know is what the 3 wire connector that is located above the neutral safety switch for the TCC needs. It has 2 black and one white wire. I was hoping someone knows how to wire it up.