I'm planning on running 3/8 nicopp lines along the frame, connected to flexible hoses on either end. The flex hoses will have an-6 fittings. What is the best fitting type to use on the hard lines? I have found both AN nuts to be used in conjunction with flaring the tube 37 degrees, and I have found compresion type fittings
I would use the flaired fittings. Factory has used them for years with great success. Would worry the compression would leak and there is the re-realing issue if you have to disassemble for what ever.
If your fuel is going to be coming out of the tank under pressure I would second the vote for using the flared fittings . I have used the compression fittings in that application for a non fuel injected car without any problems but don't know how they would work with 30-60 psi on them.
ok...thanks for the input. I had asked that question on the Hamb, shouldn't have because I couldn't really mention the fuel injection and pressure, so I got a different answer from that crowd, but of course their answers were not relevant anyway due to not having all the info. I'll see if I can pick up some flair fittings in Phoenix...and I'm going to need a 37 degree flairing tool.
The Eastwood flaring tool, http://www.eastwood.com/professional-brake-tubing-flaring-tool.html, is expensive but really make flaring an easy job. I did the brake and fuel lines on my 55 F100 and everything looks so professional. They also have a 37-degree dies available.
I used AN fittings and flaired the fuel line with my cheap brake line flaring kit. My fuel line is aluminum and even with the mismatch from AN to inverted flare it don't leak a drop.