Gates Submersible fuel line hose, PN 27000 series. It's rated to sit in fuel for years and not deteriorate.
The root issue of AN fuel line is that it does not conform to the lastest SAE fuel spec for modern fuel. Guys, we are not running the clean fuel we did 25 years ago. In many cases, it's 10% ethanol, and there are now up to 20 other additives in over 40 different mandated blends for regional use. I cannot get alcohol free automotive fuel in Missouri, and Texas/Oklahoma doesn't sell gasahol at all, and it proud of it.
I've questioned the use of braided hose from tank to motor, and I'm sticking to it. I have seen photos of early race car use from the '70s, in particular a photo of a NASCAR Torino with AN lines running from tank to motor.
On the other hand, the GT40's and MK4's in the 60's didn't - they used cotton asphalt covered Weatherhead lines exclusively. If it's meant to be a retro build, AN was never used. It's historically wrong.
IN THE DAY, it's apparent why running flexible hose from tank to motor had some advantages. Cost was not one of them. It does allow installation of the line in a semi-finished car that has been extensively modified. It doesn't kink, require short pieces coupled together, or convoluted routing that involvles the skills of a carnival contortionist to install. And the same appears to be done on aircraft.
The difference is that race cars and aircraft are inspected daily and weekly - mandatory race practice, or federally required. And at the first sign of deterioration, usually sooner by arbitrary maintenance scheduling, the hose is replaced.
Just because AN was used in the B52 doesn't mean the original hoses are still there from 1955.
Automotive standard is long term - install the lines once, and likely never look at them again. That's why automotive standard is hard lines with replaceable flex lines where they connect, to facilitate inexpensive repairs.
If someone wants to accept the scheduling of constant preventative inspection and scheduled replacement, use all the AN line you want - but as the repetitive posting on the internet shows, it's problematic. You can be setting yourself up for a issue - or catastrophic failure. It's your choice, make an informed one.
Yeah, I've got a thing about AN fuel hose use - it's just part of American Haute Rod culture, which hasn't been all that much about engineering. It's mostly about show car bling and conspicuous consumption.