Like others have said braided line is not CG approved, EVEN though a LOT of boat manufacturers install it from the factory. I don't know the real reason why it is not approved, but I think it it a bunch of BS. Someones pocket did not get padded. anyhow. I would not use the -6 braided. -6 is very hard to assemble. I have done a lot of braided hose lines in my day and used all the little special tools and tricks and it SUCKS to assemble it -8 is easier. You have to be careful when assembling -6 90's though. Just recently I have done some and even though I lubed, greased, oiled (better than a greased hog in a pig catching competition) everything up, when the fitting is pressing into the hose, it scraped the inner layer of the hose and you cant see it. I'm going to redo my fuel system using the push lock fitting. Much easier to assemble and no bloody fingers.

Im no expert by any means but the reasons I have been told for the fuel lines to be only CG approved are " The lines have to be labeled on the " outside " "FUEL LINES" so anyone can just look at it and know its a fuel line. And Second reason is so you can actually inspect the lines for cracks. If they are braided you cant actually see the hose, your looking at the pretty metal cover. And I also have been told that some surveyors will look at the date codes on the line and after so many years they will recommend that it be replaced.

buy the kool tool,it is amazing how easy and painless it makes the job become.

Fuel line being USCG approved has to do with how thick the hose wall is and the amount of vapor that can escape and fire resistance. Needless to say it also has to have all the markings on it that says its USCG approved. It has nothing to do with anything else.

To the OP's question, I would use -8 line. thats right below 1/2" ID which is going to make sure that you don't have any fuel issues ever. The only difference between 6 and 8 (besides ID) is that -6 is a bit cheaper.

I agree on the #8. It's not much more than #6 and it leaves you room for growth in the future. You never know what you may do down the road as far as power goes. You don't want to completely redo the fuel system and then have to do it again because the lines aren't large enough for the additional power you want to add.

As for the braided hose, any hose that is attached to the engine is grounded. If it touches any +12V, you will have a dead short and potential for fire. I've seen a SS braided hose that went right over the coil and when just barely bumped, it touched the +12V side of the coil. Within 1 second the SS braids on that section of hose starting glowing cherry red. It actually was stuck to the + post of the coil. Had I not pulled it off immediately, it certainly would have went right through the hose and started a fire. That can happen so quickly if it touches any + source since the hose is grounded. I don't care for SS braided hose in the first place, but I would NEVER use it on a fuel line. Push Lock hose works great. You can actually use Push Lock fittings with cg approved fuel hose. We install an Oeticker clamp on them to be safe.
Eddie

Thanks Eddie. Glad I haven't ordered the hose yet. What size rubber hose should I use? 1/2" or something bigger? I'm running a Mallory electric fuel pump. Do they make fittings that will thread into the fuel pump also?

I would use #8 hose, which has an ID of 1/2". I would imagine that the pump takes NPT (pipe thread) fittings. However, it could have ORB fittings. What model pump is it and I'll see what fittings it has.
Eddie

It's a model 4110M

According to the specs listed on Summit Racing, that pump has 3/8" NPT fittings both in and out. You would just need a 3/8"x #8 adapter to screw into the pump. You should try to use straight adapters and full flow radiused hose ends if you need to make a 45* or 90* turn.
Eddie

AN fittings and the associated braided hoses are okay but personally, I will not run them anymore. Your typical AN fittings are aluminum and they don't hold up so well over the years. I have had a few fail on me including a fitting at my fuel regulator that had cracked at the flare and leaked a substantial amount of fuel into my bilge. It could have been a bad situation if it went unnoticed.

That being said, there are a few companies that make stainless steel AN type fittings but I prefer to run steel JIC hydraulic fittings and hose. This is overkill for sure but also bullet proof beyond any reasonable doubt.