I'll try to be brief. AN refers to the original military hoses. (Army/Navy??) also called dash-(some number). They are really a way to attach flexible hoses with special ends ( terminations) to a matched special fitting. The advantages are - seals tight, moderate pressure capability ( up to thousands of PSI in some applications) , and easily removable, flexible. The number after the dash is the nominal number of sixteenthths (unsure) AN-8 is one half inch. AN-4 is 1/4 inch and so on ( get confirmation I am unsure). It is a really neat and expensive way to run hoses. Not quite good enough for aerospace but better than needed for automotive applications. Expect to pay around 10$ each termination and a few dollars per foot for hose. Making up and cutting hose can be a chore. Manufacturers inclued Aeroquip, earls supply, and many others. For a fuel pressure guage a grease gun hose and a coupler are a much better deal. If you want to go for the show look expect to spend some time and $$$. I wnt with AN fittings between the lift pump and the filter and between the filter and the VP-44. I used "pushlock" hose on the suction and discharge of the "pusher" pump. There are some vendors out there. Inform me of my mistakes please.
Attention: TDR Forum Junkies 
