4 wires from sending unit

[dsd1983]

Dropped the gas tank on my 79 cutlass. I see four wires coming from the sending unit. One is a red one that has a plug on one end that plugs into the sending unit and the other end has a single male blade that plugs into a red wire with a female plug to match the single blade. The next wire is black and what I am certain is the ground wire. Now after that I have a red wire and a green wire that are right next to each other, so what are these wires for?

Thanks

Doug

 

[88ss408]

Is it possible a newer style sending unit that is meant for efi was used? I never seen them having more then 2 wires.how many pipes are coming out of it ? you should have a 3/8 pipe and ( I think) 1/4 pipe