Gas Tank and other Questions

[Sodak]

Got a 78 chevy duel tanks and this truck has lived a hard life ,not sure if these are the original tanks/sending units or not.Basically it has three lines coming out,1 is the main line @ is a vent(to where i have no idea) and 3rd is the return.
Now my question is ...How do i go about hooking these up ,And to what, in the manual it says i needed a three port one wire tank diverter(Got it) also there is no extra port on the mechanical fuel pump and again don't know where the vent goes. would it just be easer for me two replace the sending units with a two port?

Next question.
Where do i find gas tank filler hoses? Can't seem to get themat a chain store or online that i can find.If someone can steer me in the right direction i'd appreciat it.

And finally(for now) i have a 73-74 grill and the bowtie is missing (sticker part) where can i get a new one .She just doesn't look right without it.

Thak you guys for any and all help.

Shane