Question about fuel fitting

[jmking9]

Im going to run braided fuel line from the stock tank to the carb. My question is does anyone know what fitting is required at the tank right out of the sending unit? Ive tried a 3/8 NPT to AN fitting and it doesnt fit. I dont have too much experience with this kind of thing, so any input is appreciated.

I borrowed this pic from a board member (hope he doesnt mind) to show where Im talking about.

Also should I use -6 or -8 An for the line?