a727 lines

Dash sizes, or -AN sizes, are commonly believed to have originated in the military applications. On aircraft, ships,Tanks, etc., in order to create durable and reliable hydraulic, fuel and coolant plumbing. The tough, braided/reinforced hose, coupled with thread-on connections, led early racers to buy military surplus hose,hose ends and fittings in the years following WWII and the Korean war. The racing community quickly latched onto this style of plumbing, resulting in common use in today's Performance and racing markets. The term -AN (a common abbreviation for army/Navy specification) sticks with us to this day. That's why the hose/hose end assemblies we see today are referred to as -AN assemblies.

So we refer to the hoses, hose ends and fittings sizes with the term AN, or by the term -AN. It all means the same thing. For example, "I'm plumbing my fuel system wit dash 6 hose); or "I used dash 8 AN hose for my carburetor feed." When in written form, the dash symbol (-) or the word dash might be used.

-AN(ARMY/NAVY) hose sizing is based on single and double digit identification numbers, Common sizes for performance automotive applications include -3, -4, -6, -8, -10, -12, -16 and -20The larger the number, the larger the hose diameter).

-3 and -4 sizes are typically used for brake line applications, small oil lines, some fuel line applications, pressure gauges and vacuum lines.

-6 size is typically used for fuel and oil plumbing.

-8 size is typically used for fuel, coolant and oil plumbing.

-10 size is typically used for oil , fuel or heater hose plumbing

-12 size is typically used for coolant, large fuel delivery or dry-sump oil.

-16 size is typically used for coolant, dry-sump oil or large fuel delivery

-20 is typically used for coolant (radiator hose).

What do these AN dash numbers really represent? Actually, there is a logical reason for these numbers, which otherwise might seem like made up codes. The dash number refers to the hose inside diameter, in increments of 1/16 of an inch. For example, a -10 size translates to 10/16" (5/8") inside diameter. This is an easy way to understand dash sizes. Just think of terms 1/16" increments. A -6 means that the inside diameter is 6/16" (or 3/8"). A -8 is 8/16" (or 1/2") inside diameter. Just remember that the format is 1/16".

Not to make things confusing, but those 1/16" increments are "nominal' numbers that indicate the O.D. of the hose end's internal metal tube (this tube slips into the hose). In reality , most AN hose makers actually make their hoses a bit on the tight-tolerance side, to the tune of about 1/32"smaller than the theoretical nominal diameter size, which aids in hose sealing onto the hose ends tube. So a -6 hose, which theoretically should have a inside diameter of 6/16" (3/8"or 12/32'), more than likely features an inside diameter of 11/32". Nevertheless using the 1/16" theory as your guide will help you to easily visualize what the inside diameter will be.

Yes I have a 100 page book on AN hoses. You didn't think I knew this by memory did you.