EFI plumbing issues

[dwillouby]

I am using a SBC with a Fitech dual quad EFI system. The Fitech requires a -6 return line to the tank. The system FF sold me uses a -4 return on the in tank housing (also with fuel lines that were too short). I was informed a -4 return or a -6 to -4 reducer would cause pressure issues. Any ideas? guess I need to scrap the FF parts?
Thanks

[tundra2050]

First of all, I am in no way an expert on this topic. But my understanding is that EFI requires at least a 3/8" send and return line. Maybe larger if you're running some incredible hp making machine. I ditched the 5/16" and 1/4" lines provided by FFR ( I think it's for a carb setup) for 3/8" hard lines and -6AN braided PTFE and -6AN fittings. I also went with a 340LPH in-tank fuel pump that also had -6AN fittings and inline 10 micron replaceable filter. I plan on using the braided line from the hard line to the tank via the filter and from the return hard line to the tank. I'll build braided lines to the fuel regulator once I'm ready for the engine. My biggest challenge so far was finding the -6AN male adapter fittings to the hard lines. I haven't started installing so if I'm way off, please let me know. I also don't want to send someone down the wrong path.

[dwillouby]

Thanks for the reply. Looks like i will use the Aeromotive Stealth Electric Fuel Pumps for 1983-1997 MUSTANG and -6 supply and return lines. The Fitech throttle body uses an internal regulator for up to 340lph so hopefully good.
David

[Chris H.]

I ended up using an line and fittings, worked well with my fuel rails and regulator anyways.

[Blitzboy54]

FFR sells you fuel lines that are meant for uses with fox body mustang parts. Once you move up to the EFI you will need to step up you fuel delivery system. I have used PTFE 6an with 3/8 SS lines on 3 builds. My truck right now has a 340 lpm in tank fuel pump. Honestly probably double what is needed but for a bunch of reasons that have nothing to do with your question it's what I did. I put the regulator in the back by the tank and ran a single under the chassis to the engine vs having the return upfront and running 2 lines to an engine compartment regulator.

6an is fine, some folks move to 8an but that is not necessary.