I've been using black fuel line , I think 2.5 mm ID, for about two years now and no leaks. So far, the lines still feel like they did when new and only cost about $.50. I want to replace with the braided stuff but Fastlane has been out everytime I ordered it so I haven't.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k