So I’m back to working on picking up some Parts to work on the Duster project and I desided to get some upgrades for the fuel system. Since the tiny fuel line on a 1973 model 318 is limiting for performance upgrades and 50 years old (sitting unused for 30 years from a rusty tank), best to replace it and eliminate any possible issues down the road. I’m thinking of something like the black flexible fuel line that Holley has, or something equivalent. I did metal lines on my 1970 CUDA and that was a pita. Any suggestion and info would be appreciated.

Use some braided fuel hose you can use #6 or #8an easy to work with.

6AN kits from Evil Energy on Amazon

Good luck.

Depends. Still using stock tank? Stock pump? I wouldn't use AN hose with worm drive clamps. It's not made for that and won't clamp tight enough to be safe.

Migs...Maybe not what you are looking for but I Bought some brake lines from Inline tube...www.inlinetube.com . I am also ordering the fuel pump to carb lines from them for my 69 Dart GTS...

I thought about using nickel/copper line, (NiCopp?) but I haven't done it yet.

Seems like a good application, unless someone can show me why it isn't.

I run metal tube for long distances like rear tank to ft pump.
Lighter than braided stainless hose, and doesn't abrade everything it might rub against.
Done a few fuel systems using 3/8" or 1/2" aluminum hardline, often protected by fire sleeve, that are still fine 20+ years later.
I use short lengths of hose to connect pumps and carbs & isolate vibrations.

Me Too
I used 1/2 I.D. soft drawn aluminum line from a local hardware store on my 1969 dart GTS street car, works good, last a long time

Depends. Still using stock tank? Stock pump? I wouldn't use AN hose with worm drive clamps. It's not made for that and won't clamp tight enough to be safe.

No, looking at updating to a larger tank and performance pump. still not sure on mechanical or electric pump as of yet. Plan to do it right, so I would use AN fittings.

I figure with flexible line i can keep fuel cool, easy install, minimal worry of it rubbing or rattling, easier routing without needed fabrication.

I know a guy here with an A-body car that still has the factory 5/16 fuel lines in place for the 273 that it came with, and it runs very low 12's at over 110 mph with a modestly built 408. Big fuel lines are not totally necessary until you start making serious power.

3/8" fuel line and a good fuel pump will supply enough fuel volume for most street strip cars generally speaking.

True Neil, but this rusty tank and old lines don't look like it's worth the hassle to clean up and metal lines probably full of rust. With upgraded lines, if I want to upgrade to a bigger engine like a stroked big block, the lines will already be in place for the swap.

I have -8 fragola cloth braded line front to rear for feed and return. I wish I did hardline but this was much easier and has been fine for 8-9 years now. I should probably replace them at 10 years as a precaution and then I will do hardline or PTFE.

My car originally had a 318 in it. We went OTT with the fuel line after installing a 655ci motor and having a weird 3rd gear lean out issue at the track. Originally we used a -10 line from the Magnafuel 500 pump (which has a built in -8 return) and -6 to the carbs from the regulator. We upgraded to -12 swapped the regulator and ran -8 to the carbs. It actually did help but didn't fix the problem which turned out to be two other fuel probs anyway.
We ran bulkhead connectors where needed rather than running the braided stuff through holes, it makes for a better installation and track tech likes it better.
I don't think you will need -12 line but I was surprised by how much going from -10 to -12 helped the hi speed lean out on the data logger as prior I was leaning towards "it will make no difference" and I'm sure a lot of folk will say the same. Though I'm pretty sure the fuel system will take anything I can throw at it N/A now

Fuel supply in a drag car can be challenging to get it so it has to much, more than you need
But it is absolutely mandatory if you want to be able to race and tune it without worrying about hurting the motor
My definition of too much fuel supply is if you can fatten the mixture up enough the slow the MPH down in the 1/4 mile

I use instrumentation 0,035 wall stainless for fuel lines, it's cheap, rated for a 2600 psi and 316l doesn't rust from anything . I just did my transmission cooler lines on my Ramcharger out of it too, 1/2" tube was 44 bucks for a full 20 foot stick of it. It's cheap enough to make a test practice bend and then do a good one out of a 20' stick. A couple of stainless compression to AN adapters at each end to finish it.

I wouldn't use compression fittings, even at carbureted fuel pressures. That's just me though, I'm sure people do it with success. Also, stainless is really hard to bend and flare especially anything that's over 5/16".

I'd be wary of running flexible hose front to back on a street car. Dedicated race car sure, but on the street I'd feel more comfortable with some amount of hard line. Not sure there's actually any real justification for that though since as mentioned above it's been done without issue.

My Duster is a combination of -6 'push lock' type hose and 3/8" aluminum hard line. PITA and somewhat costly to install with all the fittings etc. but that's the way I've done all my cars. Same idea as the factory setup with flexible hose between the tank and rear chassis to hard line up the frame connector then flex line to the carb or throttle body.

I do use gravel guard along the bottom where the softer aluminum line is exposed to road debris but it adds weight and a little bit of cost. I used Kevlar(?) spiral guard around a short length of flex hose where it goes through the right front wheel well. it's the same type of stuff used to protect hydraulic lines on machinery.

The stainless swagelok style fittings are rated for more than the tubing so over 2600psi, I've been using them for 30+years on high pressure ammonia lines on compressors and have yet to see one let go, or even leak for that matter. It's not some plumbing store compression fitting or brass ferrule type, these are industrial fittings. The best part is they are actually cheaper than the automotive compression tube adapters. the other way to finish is how I did the 3/8 fuel line in it. I just cut the threads off an AN stainless end, and silver brazed the ends on directly on to the tube to make it a little cleaner looking.
The .035 wall is easy to bend, even my 13 year old kid can bend 5/8 with hand benders. I do 7/8" by hand quite often for Oxygen service.

It can be tin soldered also I have tin soldered many a brass fitting into steel oil/trans pans.

I agree.