Okay, after taking off my fuel rail to change my injectors yesterday, i realized a seemingly overlooked issue with all the fuel system set-up debate thats been going on. UNLESS YOU HAVE A CUSTOM RAIL, it does not matter what size line you have going into the rail, 8AN, 6AN, or whatever, because it still has that 4AN or 1/4 inch tube between the rail and where the stock line screws in, that fuel has to be pushed thru.
SO, working with the basic laws of fluid dynamics, you could have a fire hose hooked to your rail and still only get a certain amount of fuel in there at a certain speed/pressure, cause bigger is only going to back up and create more pressure for your pump to push against.

As far as the return line is concerned, bigger is okay. You can run 3/8 (or 6AN) and be just fine. 4AN will be just fine also since its not under pressure, and since your return tube into the tank is 1/4in, (4AN) this is probably best, or at least no less better than 6AN!

if one was to change their fuel system lines to steel braided there would be no benefit if you do not do the entire system. It would basically cosmetic. like i said before, I have 100% steel braided line from the fuel pump back to the tank, this includes the small portion to the fuel rail, that is why dan posted the picture of my rail in the other post, i modded it to accept -6 lines. Like it was said in the other post, not to be a punk or anything, but if you are going to do the steel braided thing, do it right, do all the lines or it just ain't worth it. if money is the issue, then maybe you shouldn't be considering this mod because it truly is an expensive affair to do it right.

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james

No, no! i agree with you completly! Im just saying in general, since some people have posted running bigger lines connected to stock fittings that its just as you said, its only cosmetic. Thats why i also said, UNLESS YOU HAVE A CUSTOM RAIL, as you do, (and as you mentiond a custom pump assembly) that any bigger is not going to get you anything.
Im not posting this stuff to throw doubt on other peoples set-ups, just giving out some info that i figured out and that wasn't very clear when i was looking for answers.
i like your custom set-up, and i may do that later on when i need to. But right now, its not about money, its about doing it right without un-needed overkill. (not an accusation to anyone...)

How did you mod your rail to accept a 6AN fitting INTO the rail? the pics only show the out side? i would like to see so i have an idea of what is needed when i do it.

I understand you completely, from what I gathered from the other post it appears that most people trying to do the steel brail line swap are a little too concerned with cost. In my opinion if you are going to do this conversion you must realize that it will cost! I think to do my entire system it was like 300 dollars. With regards to the fuel rail, what i did was take a 95 rail, (you could use a 97-99 rail but it will be modification will be completely different) i cut off the original in port and tapped the remaining hole to accept a set screw. i threadlocked and siliconed the set screw and screwed it into the old hole. then i drilled a large hole on the side of the rail and tapped it to accept a -6AN M to M coupler. this threaded in using a copper washer and silicon for sealing. the other side was different (remember the 95 had the FPR on the othr end of the rail) i removed the fpr and cut off the snap ring flange. then i took a STEEL -6AN M to M coupler and found washers that had a ID the same as the OD of the AN fitting and an OD the same as teh ID of the fuel rail FPR section. I took 5 of these washers to get the proper stack height and placed a ring of solder between each washer.I then placed a ring of solder around the base of the AN fitting and placed all these parts in the rail end. kinda like

RAIL ||||| AN fitting where | are washers

I then heated the area with a propane torch and reflowed the solder and added additional solder as necessary. i let it cool and sanded all the sharp edges and painted the rail black. that was it, the newer rails have very thin walls on the ends, so if you were to do it on these you would probably have to solder a steel fittingon both sides.

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James

sweet :7
Michael 99gs
HRC Stage 2 @12psi :D
Stage 3 process begins gathering parts for rebuild
2GNT Member #32

http://www.dreamwater.net/purplebeast

I agree with Jamesman, my complete set up cost me about $600-$700 including the sfmu.
some people though might be looking to just relocate their sfmu in the engine bay thus needing some kind of return line. in which case a 4AN return set up is not a bad idea, and not that expensive.