So if you wanted to buy regular barbed fittings to install in your typical 6AN application, the thread diameter is SAE 9/16 with 18 threads per inch. For those that don't know, the number before the "AN" indicates how many 16ths outer diameter the intended hose is supposed to be, nominally. So 4AN = 4/16" = 1/4" hose for example.

This was originally linked in this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/using-rubber-fuel-line-aeromotive-fpr-904963/ credit to keithrulz for finding the original source page

 

Excellent - thank you!