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  #1  
Old 06-25-2007, 11:25 PM
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tml1138 tml1138 is offline
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Default Upgrade fuel system

I want to upgrade and restore my fuel system to new on my '71 Scamp. It needs it badly. I have a Holley 4bbl 0-1850 on the 318, and have been running it with the original 5/16" lines adapted up to 3/8" to fit the carb hookup. Since I need to redo the whole system, I want to run 3/8" throughout from tank to carb. What all do I need to make this happen? Obviously the sending unit and fuel pump will need to be 3/8", but where exactly can I find these parts for the most reasonable prices? I just want to run this for now as a decent street crusier with a little bit of 4bbl carb pep. But there are some forks in the road that I'm running into.

Fuel tank: which type? I've been finding that there are two types of vapor/vented tanks for the '71 years. (4 and 1?) Does it really matter which I have or is that just for emissions that were coming about in the early '70's?

Fuel pump: best to go with stock type? mechanical or electrical? at engine or at tank? again I just want to get this for some typical street driving right now, no fancy stuff. (Someday when I rebuild or drop in a new engine....) I've been looking up some that have higher psi but I believe that's just for serious racing and then I'd also need a regulator to drop the pressure down.

Anything else I'm missing? Jeez, I figured this would be a relatively simple job but after looking up pricing on various fuel system parts there's more options than I realized.

Thanks!
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  #2  
Old 06-26-2007, 03:20 AM
cudabob496 cudabob496 is offline
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I stuck a 12 gallon fuel cell in the trunk of my Cuda. Seems for your engine combo the 5/16 should work. I went to a 3/8 inch because my motor is a 496 I run a mechanical fuel pump and have a Holley regulator to keep the pressure around 7 psig. I think the regulator costs around $30 in summit catalog. Why does your system need upgrading?
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Old 06-26-2007, 10:15 AM
peg leg peg leg is offline
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Default Inline tube

has the lines you need. I used their stainless whole-car brake line kit, and the stuff is top quality. Fits the car like it came from the factory with it.
Google search inline tube. They are in Michigan, and advertise in Mopar Muscle.
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  #4  
Old 06-26-2007, 05:45 PM
wilks3 wilks3 is offline
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Try Paddock Parts or Mancini Racing for the sending unit upgrade. I'm sure you can buy the 3/8" fuel line replacement upgrade from one of these places to. If not just run the new fuel line yourself, thats what I did. Steel or aluminum. Aluminum bends easier and in my opinion ok to use on street.
If engine is stock to mildly hopped up, stock pump will work fine, then no regulator needed.
The fuel tank is a wash, both will work. Good Luck!!!
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  #5  
Old 06-26-2007, 07:21 PM
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Alum lines have a better chance of getting a small air leak in them, like when a straw has a crack in it, no pop comes out the crack, and all you get the harder you suck is air, not good on a hot day, vapor lock.
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Old 06-26-2007, 09:03 PM
DusterW2 DusterW2 is offline
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Try Year One for the 3/8" pick-up/sending unit. They sell a bolt-in unit ready to go. Also get a new locking ring and gasket to go with it. They also have gas tanks and straps if needed. John
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  #7  
Old 06-26-2007, 10:23 PM
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Quanta will have the best price on the sender.
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  #8  
Old 06-26-2007, 10:48 PM
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I'm wanting to "upgrade" for the future. I don't plan on running a stock 318 in it forever, and so I'd like to step it up to 3/8" now even though I don't absolutely need it right now. What does need immediate attention is the gas tank and possibly other related parts as for one it's gotta have junk in it from 35+ years of use and also it leaks somewhere at the top of the tank as if I fill it, I've got gas spillage everywhere. Might be a bad tank, or seals/grommets for the sending unit or maybe filler tube.

So I figured while I'm dropping the tank for inspection and replacement, I'd just do new fuel lines overall and freshen up the 35+ year old system, with 3/8" to boot since it will be more than stock at some point.
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Old 06-27-2007, 12:01 AM
cudabob496 cudabob496 is offline
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I think a 5/16 would handle up to 400 hp, if not more. I'd spend the money on "go-fast" goodies.
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Old 06-27-2007, 02:16 AM
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I would think the filler tube would be the likely suspect for the leak/spillage (I have the T-shirt ) I'll agree with cudabob on the 5/16 capacity; on the other hand if you're going to redo the entire fuel supply system you may as well go 3/8". Just be aware that the 3/8" line will be the cheapest part of that re-do. All the other points (pick-up, pump in & out, carb inlet) will need to be sized accordingly or you lose the advantage of the larger line. But I'm sure you've already figured that out. Me, I had the tank cleaned and lined, renewed the filler pipe, and decided to stay with the 5/16" for my street 360. The other thing is whether or not your car had a vented or sealed tank. The sealed ones actually vented to a vapor recovery system, and have a return line from the fuel pump as well as a 3rd line to the charcoal filled canister for the vapor recovery. That system may cause fuel spillage if it's damaged or corroded. It doesn't cost any power, so it might as well be working properly.
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  #11  
Old 06-30-2007, 07:53 PM
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Thanks for the info. I've dropped the tank, and it's amazingly clean inside. Even every last drop of fuel looks good. No silt/deposits/dirt.

I'm sort of at a loss what to do with the vapor recovery system. Being a '71, it didn't have the charcoal canister yet (I've just read the valiant.org site that claims that wasn't a part of the vapor saver system until '72) and there is 4 vent lines that go up into a tube in the trunk and then a 5th line that goes up front to the breather cap on the valve cover for the crankcase vapor. However, the gas tank is a replacement as it's the later year tank that only has one vapor saver vent tube instead of four like the early '71 years. The four lines coming out of the large vent tube in the trunk go to nowhere (since it's the wrong gas tank) and the vent line going up to the front is broken anyhow.

I've ignored these issues for long enough, and would like to fix it right if it's needed. The original 2bbl setup had vapor lines going from the breather cap to the carb and air cleaner. Since I put on the 4bbl Holley 1850 and chrome air cleaner, there's nowhere for the vapor lines to go. Or is there?

Also, how do you remove the fuel gauge sending unit from the tank? Shop manual calls for some special tool.....
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Old 06-30-2007, 08:31 PM
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ehostler ehostler is offline
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Use a screwdriver and a hammer. Align the screwdriver with the retaining ring and hit the screwdriver with the hammer. start with taps and hit harder, as required.
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  #13  
Old 06-30-2007, 09:15 PM
cudabob496 cudabob496 is offline
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I just plugged the vent lines going up front so I wouldn't have to smell gas fumes. They were no longer hooked up to the charcoal canister when I got the car.
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Old 06-30-2007, 11:14 PM
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Well, you can plug vent lines, I guess; but the tank has to have some kind of vent to atmosphere or there'll be an issue getting fuel out to the carb. (Think tank collapsing as fuel leaves and air can't replace it. Try and find a vented cap. Not smog-legal on vapor recovery cars but yours wasn't so any vented cap would solve your problem
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  #15  
Old 06-30-2007, 11:17 PM
dodger1 dodger1 is offline
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Also, re removing the sender, Ed's right except I think I'd rather use a brass drift. Sparks from a steel screwdriver would be unwelcome here!! It doesn't take much movement, only the width of one tab.
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  #16  
Old 07-01-2007, 03:09 PM
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as far as the vapor recovery lines, remove em. then, use a vented line from the filler tube like one would have on a 70 duster. vents the top of the fillertube through a couple of loops, back down through the rubber seal on the floor to outside air.

as far as the 5/16 vs. 3/8 dilemma, it depends on what the future motor is gonna be. anything like 400+, go 3/8. if its gonna be a 300HP motor, 5/16 is fine. always overbuild plumbing in my opinion, as you never know exactly what teh future may hold. at the moment, you already have a 3/8 in on the holley, and any good aftermarket pump will be 3/8 in. i like the carter and summit mechanicals myself, as you can swap it on the side of the road with a stocker anywhere in the country. id try the inline tube that was recommended. i bought all my brake lines from classic tube and rebent every single one of them. so dont buy theirs.

Michael
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  #17  
Old 07-01-2007, 05:58 PM
Duster367 Duster367 is offline
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Quote:
Originally Posted by tml1138 View Post
I want to upgrade and restore my fuel system to new on my '71 Scamp. It needs it badly. I have a Holley 4bbl 0-1850 on the 318, and have been running it with the original 5/16" lines adapted up to 3/8" to fit the carb hookup. Since I need to redo the whole system, I want to run 3/8" throughout from tank to carb. What all do I need to make this happen? Obviously the sending unit and fuel pump will need to be 3/8", but where exactly can I find these parts for the most reasonable prices? I just want to run this for now as a decent street crusier with a little bit of 4bbl carb pep. But there are some forks in the road that I'm running into.

Fuel tank: which type? I've been finding that there are two types of vapor/vented tanks for the '71 years. (4 and 1?) Does it really matter which I have or is that just for emissions that were coming about in the early '70's?

Fuel pump: best to go with stock type? mechanical or electrical? at engine or at tank? again I just want to get this for some typical street driving right now, no fancy stuff. (Someday when I rebuild or drop in a new engine....) I've been looking up some that have higher psi but I believe that's just for serious racing and then I'd also need a regulator to drop the pressure down.

Anything else I'm missing? Jeez, I figured this would be a relatively simple job but after looking up pricing on various fuel system parts there's more options than I realized.

Thanks!
I made my own pickup. I use a piece of 1/2 aluminum fuel line matched it to the shape of the 5/16 line in the pickup . Then I used a diegrinder to remove the 5/16 line and enlarge th hole in the pickup.I slash cup the end that goes inside the tank then I mocked it up looking through the filler tube hole to make sure the pickup sat in the tank properly. then I used moroso a/b epoxy to secure the tube in the pickup. It worked great no fuel cell to deal with and my gauge still worked. It cost about 20 bucks to do. The reason I went this route is at the time nobody made a hiperf sender and I was too broke from building my engine to buy a cell. If your handy give it a try or you could just by one like everyone else said. p.s it never leaked it's been 5 years.
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  #18  
Old 07-03-2007, 01:26 PM
BillyBob BillyBob is offline
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Can anyone explain why the factory only used 5/16" lines for the 426 & 440 engines & everyone here feels the need to go larger?
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  #19  
Old 07-03-2007, 04:40 PM
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it was my understanding that the max wedge, six pack and hemi cars used 3/8, and the rest got 5/16.

its all about flow rate. more power demands more fuel, which requires a bigger line.
Micahel
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