[Snake72]

Thanks Tigger, the shop was my father in laws, every tool and piece of equipment you could ask for. I really need to clean up the parts boxes..

After doing some research, my mystery wiring harness that went into the firewall by speedo is the TCS harness. The wiring connected the idle stop solenoid on carb, TCS switch on trans, passenger side water temp sender to a relay inside cab and the fuse box/ign on plug. I'm tossing this whole system, not needed for my set up. Sounds like most TCS were unplugged soon after the trucks were bought anyway