What flare for fuel line?

[Chargerguy74]

3/8 aluminum tubing to NPT fitting. I've read it should be a 45 degree flare and not 37, but does it matter if it's a single or double flare? Would it be different if it was steel or stainless steel tubing? Thanks!

[BSB67]

You don't use flare fittings with NPT. 

[Chargerguy74]

Edit:

Sorry, I think I was way off here. I'm thinking I actually require a 37 degree AN flare. The fitting I have is 6AN female to "3/8 tube." I thought the 6AN just referred to the other female end. I've done more reading and using a 45 flare on 37 degree AN fittings in low pressure fuel systems is fine. Just wondering if I need a specific flare, single or double, for this fitting?

Here's the fitting in question http://www.performance-world.com/ProductDetails.asp?ProductCode=93606

[Chargerguy74]

I think I found all the info I needed and have learned a few things about automotive fittings. No flare for this fitting.