Sending unit ports

[AKguy]

Okay, received two new units for my main and aux saddle tanks, Spectra FG05H models that will be feeding/returning from, my Sniper EFI. They have two ports, one 3/8 for the supply and a 5/16. Is that 5/16 intended for the return? If so, will I need to vent them like the originals that had a 1/4 port as well? Thank you.

 

[Vbb199]

Return is 5/16, but holley specifies 3/8 send and return I think?

In this thread below, I was discussing my setup with someone with my holley efi feeding my 502 ci

In my k5, I'm using the factory tbi braided lines for send and return, and just did 14mm and 16mm adapters to go to the 6an ports on the back of the holley efi.

https://www.gmsquarebody.com/threads/fuel-lines-for-fi.30097/#post-59049

I'd say the venting is just as important...
In order to have a steady, nice flowing fuel system sending and returning, you need a vent... Otherwise it'll get.... Hydro locked? In the lines

 

[AKguy]

Cool, yeah, Sniper recommends 3/8”, EFI Sustem Pros suggest 5/16” returns, so I think I will just use the factory 5/16” for vent and use the AN 3/8” thru fittings for the returns. Thanks.

Edited to correct info.