Fuel Line for SBC 350

[1971LT1SWBPOSI373]

Ok, here it goes guy's. I want your professional input for this situation!!!

I'm mildly working over a 350 small block chevy (1976 block) in my truck. I put on an Edelbrock "Performer" aluminum intake manifold with a Carter AFB 9635 on top (625 cfm, also the same as an Edelbrock 1402). My stock fuel pump was weak, so I replaced it with a Holley 12-834 diaphram fuel pump, and I indexed the fittings for my application prior to installation. My problem lies with the fuel line connecting the two.

My stock line was trash, and it's nowhere near where I need to go. Keep in mind the original is double flared steel tubing. I work at an airport, and have some experience working with and manufacturing lines, so I figured I would just whip one up. I soon found out no easy task, because of the close proximity of the 90 degree bends that I need to make at the flared ends. To make a nice double flare, it requires a substantial tool to secure the line, and then once it's flared then getting the bend in there close is another problem that I couldn't get around. I tried several different methods without any success (I'm using 3/8" steel brake line). Finally last week I decided to give it a go with just a single flare. I worked on it for about 2 hours and I'm nearly done. Do you think a single flare line is good enough???

I called Pacific Automotive Warehouse this morning just for kicks to see if they would have a double flare steel line, and to my luck they don't. They suggested the steel braided hose, but I want a real fuel line, not something I have to continually keep an eye on for chafes, manifold burn, or leaks at the fittings. The tech at Pacific mentioned that everybody is now using single flare aluminum fuel line that they manufacture themselves. I would think aluminum might crack under engine vibration after age hardening, what do you think? It certainly would be much easier that steel. Or what about copper??? It's softer and a little more flexible. Give me your input. I want something I can install and forget about, and not worry about burning up my vehicle. TJ

[Tx Firefighter]

TJ, I've been an A&P since 1994, so I know what you're thinking here.

On cars, use single flare on everything but brake lines. I've built many fuel lines out of 3/8 hardline and never had a single problem with single flares. Remember, you're only dealing with 5 psi or so here.

If you were ever building a brake line, double flare it for sure, but that's high pressure and even higher safety factor. No brakes= wreck

I agree (as well as the FAA, I'm sure), aluminum fuel lines have no safe place on an engine. The aluminum will work harden and crack. It's just amatter of when, not if. I think the same thing when I see folks using copper fuel lines. That also has no place on a vibrating engine.

[1971LT1SWBPOSI373]

That's what I'm thinking TXfirefighter. I just noticed the original line is a double flare so I gave it a go to manufacture one. I don't want any rubber connections under the hood, they always seem to be a source of trouble. Another hour or so of work and I should have my line complete. Aluminum seems like a bad choice.
PS We fly N-1 out of DCA. TJ

[poff]

I had a similar issue with an Edelbrock pump and later model Q-jet. I bought a premade 4' x 3/8" brake line and used the existing flare for the tight bend. The only drawback was the $60 Ridgid tubing bender that makes tight 3/8" bends. The tri-benders they sell at most places do not work near as well as the heavy-duty single benders. I made one for my self and am going to help my buddy with the same engine swap I did so it is worth it. I used a 45 degree brass fitting at the pump before the line to get a better angle.