Duel Tank Sending Units

[70'sKool]

I have a 1985 C30 gasoline fuel operated, I am in the process of converting to diesel fuel (cummins). I am wanting to know if I use the diesel sending units will I have to ad wiring? The diesel units have a extra plug-in don't know what it's purpose? Trying to locate a schematic of wiring diagram for diesel fuel sending units. I do have duel tanks three outlets one plug-in and a ground. The after market diesel units have three outlets two plug-ins. Can I replace the gas units with gas or do I need the diesel units? Below are links to the gas and diesel differences.
Any help will be greatly appreciated.

http://www.rockauto.com/en/catalog/c...ding+unit,4436

http://www.rockauto.com/en/catalog/c...ding+unit,4436