fuel sender unit 5/16 or 3/8?

[Dartnewbie]

Is there really a difference between the two and how do I know which one I have? Seems my gas gauge likes to die after going down to 1/8 tank but works above it so I assume the sender is going bad. Does 1/16" really make a difference if a rubber tube is used to connect the fuel line? If I happen to get the wrong size, could I still use it or do I have to make sure I get the correct size the first time?

 

[Burntorange70]

If your running a S/6 the 5/16 will be more than good.

 

[Dartnewbie]

Looking on ebay I noticed most if not all 3/8 senders have 2 outlets and the 5/16 have one. Does this mean the 3/8 with the extra outlet are used with electric fuel pumps? I think the 5/16 is what I need anyway since the 63's only came with the /6 and I do believe I only have the one outlet on the sender. Has anyone tried the senders for around $53 from ebay?

 

[idrift]

I have one from Vans that works ok.

The extra was for a return line. I just capped mine off.