Engin swapped, water temp guage not working. Need help(pics)

[Lil Ape]

Any help would be appreciated on this problem. So my water temp gauge is the only gauge in the cluster not working, and it's an important one. Now the truck is an '83 and originally came with an I6 and had a 350 swapped in later on.(bought it like this)So I'm not sure if wiring was different from a truck that originally came with a 350. Like switches, plugs etc.

Now from i understand, this is the water temp sender unit, typically found between cyl 1-3 on driver side. But it's installed between cyl 6-8 on pass side. because the driver side is plugged.

Driver side


And correct me if this is wrong, but i think this is the plug for the temp sender. If it is, I don't think it stretches all the way over to driver side cyl head, which is why I think the sender unit is installed on pass side and driver side is plugged up. And as you can see, the temp sender unit and plug do not match. What I need to know is if there is a temp sender unit available that will thread into a 350, but also be able to fit the plug shown in the pic below?


And there is another problem I found, there are three wires for the plug that hooks up to the temp sender, but one has been completely cut off(or so it looks?) and another doesn't lead to anything, it just hangs. Leaving only one wire leading to something. Does anyone know if this is going to cause a problem? this truck is kinda a wiring mess. And I don't know crap about wiring and electronics.