When I bolted the original 1972 tank back into the cab, I went ahead and hooked the EEC system back up. Except after the 5/16" line comes through the floor I will route it back along the frame rail under the bed and install a check valve in the end of it. Make sure the tank vents correctly. Originally that line would have ran up to the engine bay and into a charcoal canister.
I also reinstalled the seat for the last time. After all these years that the seat adjuster not working, I finally got it to work as it should.
Gary