The fuel fittings on an EFI Fox body car are Spring Lock fittings.  At the connection between the engine fuel lines and the fuel lines on the body the female (cup side) of the fittings is on the fuel lines on the body. 

So here's your problem, you need both a 5/16" and 1/4" female spring lock to connect the engine fuel lines to the fuel lines from the tank to the engine fuel lines.  The 5/16" fitting is readily available, and even available as an adapter fitting to connect directly to -6 AN.

The issue is the 1/4" fitting, which is not reproduced.  Mustangs Unlimited used to sell them, but they are listed as NLA on their website now.  I tracked them down to Ron Morrison (who was MU's supplier), and actually emailed with Ron to discover that the supplier that made them no longer produces them. 

At this point your option is pretty much junkyard.  I will say that the return lines on the V8 cars were 1/4" and I beleive the supply lines on 2.3 cars were also 1/4", so it shouldn't be that hard to find. 

When you reuse the fittings you can just connect them to 1/4" or 5/16" rubber fuel line and then on to new hardlines to the tank.  You could probably use worm drive clamps to secure them, but I prefer Oetiker clamps like these:

https://www.oetiker.com/en/Products#/?l0=A7D278F8664B424DA07D0E74E96A6B8A&l1=857A6B4A67774216A3AAE58752B204A9&l2=FB521EC93BE240B590F0358FEC73F269

The 153/154 and 101/151 are the series you would want to use.  Not expensive at all and should be available at your local NAPA.  If not then a local hydraulic shop will definitely have them. 

BB, I too like the Nylon, but the aftermarket fuel lines for my Fox don't have the correct barbs for using the Nylon.  The Nylon line should go on metal line that has three barbs right in a row.  I think that's how they got away with not having to clamp or crimp them in any way.  I suppose I could cut and flare the hard line and then go from inverted flare to hose barb, but I don't really have the right tools to flare stainless.  I've used a standard flare tool on 3/16" stainless brake lines before, but I've broken a lot of dies doing that too.  I wouldn't even try it on 1/4" let alone 5/16"; its just too hard.

Now if you're making up your own lines anyway the Nylon is definitely a better choice than rubber.  I'll just have to keep an eye on the rubber sections with plans to replace them every 10-15 years. 

I'd really like to get a good flare tool that can handle the stainless, but all the ones I've seen are like $300, and I just can't justify it yet. 

Okay, cool, and thanks.  Eastwood was probably who I was going to buy from anyway, but the reviews seemed spotty.  I trust you more than a bunch of people I've never seen or heard and don't know what level of competence they have.  Reviews are good, but like anything else you've got to consider the source.  A thumbs up from you is worth two dozen mixed reviews in my book. 

Oh Poncho, that guy is brilliant.  I used the flairing clamp to push mine onto the fitting with the fitting held in the vice...worked okay.  But his idea to use the calking gun....absolutely brilliant.  Thanks very much.

BB