Actually, the size corresponds with the OD of hard tubing. -8AN is 1/2 inch tubing, whether its 0.035" wall, 0.065" wall or any other wall. With flex lines, it really doesn't correspond with anything other than a nominal hose/line size. A -8 braided hose has neither a .500" ID nor a .500" OD, but its OD is in the general neighborhood of 1/2 inch.
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Jeff Chambers
Trophy Stock #3
11.97 Seconds / 114.5 MPH
Chambers Racing Team