Got a look at the new poly tank and the sending unit area. The wire that is connected to the center of the send unit is orange. There is another wire running in the same harness that is brown and is a bit short to make it to the send unit with a male spade connector on it. Any chance that yellow wire is a ground? Possibly a remnant of this 68 being converted from 24 to 12 volt? Be easy to connect to that yellow for ground rather than auger a new hole. Can do it but...someone had replaced the fuel line with rubber hose at some point and punched a hole in the very bottom right of the side screen to route the hose. ie can"t completely remove screen as hose passes through it. And 2..I have the loader mounted back on so drilling in there will be a tricky prospect.