Many of the considerations concerning the placement of brake lines apply to the fuel system as well. And while steel and stainless steel are the recommended materials for hard lines, aluminum tubing is sometimes used.
Aluminum tubing is light-that's why it's often found on race cars-but it chafes easily and needs more support than steel or stainless steel. For most carbureted applications, 3/8-inch line is adequate, although high-horsepower engines may require 1/2-inch for enough fuel volume.
When plumbing the fuel system, keep in mind that today's gasoline additives (including alcohol) will cause conventional hose to deteriorate. Plan on replacing any rubber hose in the system every two years, or bite the bullet at the outset and buy the best braided hose with an inner liner you can find.
Ready, Set, Plumb
Before you begin to plumb a truck chassis, here are some suggestions from the experts at Pure Choice Motorsports:
• Identify the type of plumbing you want to use (stainless steel or steel).
• Match the fittings to the type of flare used: AN fittings use 37-degree flares, SAE use 45-degree, double-inverted flares.
• Use quality tools for installation to prevent rounding off fittings.
• Do not over-tighten fittings. AN fittings should be snugged finger-tight then tightened approximately a quarter-turn. While 45-degree fittings require slightly more torque to seal, over-tightening should still be avoided.
• Use anti-seize on all aluminum-to-aluminum or stainless-to-stainless fittings.
• Use sealer on pipe threads with the tape or sealant starting on the second thread to keep from contaminating the system.
• Keep all lines as far away from heat as possible.
Take a look at the following photos for a few more tips and tricks on plumbing a chassis.