Difference between -6 and 3/8's fuel hose.

[71LS5Formula]

I need some advice. What is the difference between -6 fuel injection line and 3/8 fuel injection line. Thank you.

[sjaroslo]

My understanding of the AN sizing system is that the "dash" number is the number of 16ths of an inch, therefore, "-6" is 6/16" or better known as 3/8ths....

[71LS5Formula]

So I should be able to use standard 3/8s fuel injection hose instead of the really expensive stuff.

[TheJDMan]

AN plumbing is sized in 1/16th of an inch. So for example -4 is 4 1/16th or 1/4", -6 is 6 1/16th or 3/8", -8 is 8 1/16th or 1/2", etc. So size wise -6 and 3/8" are the same thing. How you connect that hose to your lines is a different subject. Don't try to install AN fittings on generic auto store fuel line.

[CarlC]

AN is short for Army/Navy, a military specification used going back nearly 80 years to commonize on sizing.

For hose, the sizing is based on the bore size. Hence, as mentioned above, AN6 is 3/8" bore.

For hardlines, it's the O.D. So, the bore of the tube is based on the O.D. - 2X the wall thickness.

A really good read on this and fasteners is https://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069