Thoughts on Fuel Line Size

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65 Dartman

65 Dartman

1 of None 65 Dart Sedan Delivery
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5/16ths fuel line seems to be pretty much standard on most Chrysler vehicles. The 67 Charger I've recently acquired has that size line as well. Since there's no motor or transmission in it, I've going to use what I've got available to me and that will be using a rebuilt and slightly upgraded 58 392 Hemi in the Charger. I suspect 5/16th fuel line was probably used for that motor back in the 50s. Would you stick with the 5/16th already in the car or upgrade the line to 3/8th?
 
Run new line at least 3/8 , you don't want to run a new engine on 40 some year old fuel line
 
I'm upgrading the line in my '67 Barracuda to a 3/8". I asked Mike at MRL whether or not my 5/16" line was going to be adequate for the 408 that he's building for me and he recommended the larger line.
 
Somewhere out 'there' is a chart that shows what HP each size can support depending on the supply pressure. It's a good thing to have, wish that could find it again.

What the chart doesn't take into account is the age of the tube, it assumes new. And you know what happens when you assume something.....
 
duster731 said:
I'd do 1/2 or -8 and be done with it
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yup, it's cheaper to go faster. Herb Mcandless told me that on the phone, when I had his shop port my heads years ago. he says, you know your gonna want to go faster, so do it right the 1st time. I live by his advise from that point on. saves you money in the long run
 
that early 392 hemi isVERY heavy. be for you put it in get the heaviest torsion bars you can get. i put a early 392 hemi in a 1959 ply. it was so heavy i had to cranked the height bolt till it bottomed out. that made the rubber bushings pound out. above all do NOT bottom the adjusting height bolt. AND it will not go around a corners any more. it will weigh 200-300 lbs more than ANY engine that the car is made for.
 
moe7404 said:
that early 392 hemi isVERY heavy. be for you put it in get the heaviest torsion bars you can get. i put a early 392 hemi in a 1959 ply. it was so heavy i had to cranked the height bolt till it bottomed out. that made the rubber bushings pound out. above all do NOT bottom the adjusting height bolt. AND it will not go around a corners any more. it will weigh 200-300 lbs more than ANY engine that the car is made for.
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Hmmm...........


OEM Mopar Engine Weights

Here's a small list of [approximate] weights for stock engines.
Note most of these are fully dressed engines with stock parts.
We all know the savings to be had with aluminum intakes, ect...

331/354 Hemi with alum. intake and water pump - 504
392 Hemi with alum. intake and water pump ------ 564
Slant 6 --------------------------------------------- 525
273-340 ------------------------------------------- 525
360------------------------------------------------- 560
361-400 ------------------------------------------- 620
413-440 ------------------------------------------- 670
426 Street Hemi ----------------------------------- 765
 
Bad Sport said:
Hmmm...........


OEM Mopar Engine Weights

Here's a small list of [approximate] weights for stock engines.
Note most of these are fully dressed engines with stock parts.
We all know the savings to be had with aluminum intakes, ect...

331/354 Hemi with alum. intake and water pump - 504
392 Hemi with alum. intake and water pump ------ 564
Slant 6 --------------------------------------------- 525
273-340 ------------------------------------------- 525
360------------------------------------------------- 560
361-400 ------------------------------------------- 620
413-440 ------------------------------------------- 670
426 Street Hemi ----------------------------------- 765
Click to expand...

I'd seen this chart before and I find it hard to believe it's accurate. When I put my 331 on my one engine stand it looked like it couldn't handle the weight. (I couldn't keep it from sagging) The same stand with our 400 (512 stroker) on it was no problem. Both engines fully dressed. I never weighed either but it really, REALLY seemed like that Hemi was a good amount heavier. I found a different list of Mopar engine weights on http://www.dippy.org/forum2/index.php?topic=1474.0


Chrysler Corporation Passenger Car Engine Weights

Below is a chart showing approximate weights for various Chrysler Corporation passenger car engines. All engine weights are stated in pounds.


Chrysler 331 Hemi --------------------700
Chrysler 300 Poly V8 ------------------691
Chrysler 354 Poly V8 ----------------- 691 - 700
Chrysler 354 Hemi -------------------- 720
Chrysler 392 Hemi --------------------740
DeSoto 276-341 Poly V8 ------------- 675
DeSoto 276-291 Hemi ----------------630
DeSoto 330-345 Hemi --------------- 670
Dodge 241-325 Poly V8 -------------- 645
Dodge 241-270 Hemi -----------------580
Dodge 315-325 Hemi -----------------610
Dodge Viper V10 ----------------------716
Dodge Viper V10 (1997) --------------648
Dodge truck V10 ----------------------816 - 836
Mopar Slant Six ----------------------- 475
Mopar 277-301-318 Poly "A" V8 -----600+ (estimate - see notes)
Mopar 273-318-340 "LA" V8 ---------525
Mopar 360 "LA" -----------------------550
Mopar 350-361-383-400 "B" V8 ---- 620
Mopar 413-426W-440 "RB" V8 -------670
Mopar Street Hemi ---------------------765
The only engine shown that's more than 200 pounds different is the slant 6, but it does show those old Hemis to be pretty heavy nonetheless. I don't know if their list is accurate either.
 
Trust me. The early Hemis all weigh around 750 give or take. I got one haning on the engine stand.

Aside from that, 5/16 fuel line will support 600 HP. It's not the size, but the volume of fuel delivered. As long as you have an adequate pump, you will have zero issues.
 
Go 3/8" or -6 all the way. When I did my Duster, my buddy bent up a new 3/8" hardline from tank to pump, then I went black -6 braided pump to carb with an Earls inline filter.

Also, just watch for your fuel pump inlet/outlet size too. Alot of the stock type replacement pumps are 1/4" NPT! I upgraded to an Edelbrock mech pump that's 3/8" NPT in and out so it's true 3/8" (or -6) the whole way front to back and back to front. As well check your sending unit! If original it's probably 5/16", you can get 3/8" replacements nowadays, which is what I did as well. Figure this way I'm covered for 99% of my engine power goals.

Ditch the 5/16" stuff, it's probably not in so good a shape anyway.
 
duster731 said:
I'd do 1/2 or -8 and be done with it
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i agree.... yea i know its really overkill but is it really much more going to 1/2"? you are replacing it all anyway, and this way if you ever decide to go nuts you have the fuel system to support it... gonna change the sending unit too? thats only 5/16 too.. can sump the tank too i guess.
 
GEO said:
Run new line at least 3/8 , you don't want to run a new engine on 40 some year old fuel line
Click to expand...

I wouldn't either; however, the guy I got it from (a Mopar buddy), installed a brand new fuel line back in the late 90s when he was working on the car and it's never had fuel run through it!.

duster360 said:
3/8" will be plenty big for that 392.
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It seems the general concensus is to go with the 3/8ths line. I should be able to pick up a new 3/8th line while at the Nationals. I'm thinking that down the road I will see about converting it over to a FAST, Atomic, etc style EFI. The new 5/16ths could be used as a return line if I go with a return system.

abodyjoe said:
i agree.... yea i know its really overkill but is it really much more going to 1/2"? you are replacing it all anyway, and this way if you ever decide to go nuts you have the fuel system to support it...
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Other than going with EFI later on down the road, this car will only be a cruiser. Won't be going nuts on it lol!

abodyjoe said:
gonna change the sending unit too? thats only 5/16 too.. can sump the tank too i guess.
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I have to buy a gas tank as there's no gas tank in the car. It's a no brainer to use a 3/8th sending unit as well to match the rest of the system.
 
moe7404 said:
that early 392 hemi isVERY heavy. be for you put it in get the heaviest torsion bars you can get. it will weigh 200-300 lbs more than ANY engine that the car is made for.
Click to expand...

No doubt the 392 is pretty heavy and looks to be about the same weight as the 426 Hemi on the list 1967 'cuda posted below. When my Mopar friend was working on rebuilding the front end, he reused the stock T Bars that came with it for a 383-4 barrel. Larger T Bars are definitely on the agenda as are disc brakes. The stock 10 inch drums (all completely rebuilt BTW) gotta go. The rest of the front end is all new as well!

1967 'cuda said:
I found a different list of Mopar engine weights on http://www.dippy.org/forum2/index.php?topic=1474.0

Chrysler 392 Hemi --------------------740

Mopar Street Hemi ---------------------765

I don't know if their list is accurate either.
Click to expand...


RustyRatRod said:
Trust me. The early Hemis all weigh around 750 give or take. I got one haning on the engine stand.
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That sounds about right from what I've read also.
 
RustyRatRod said:
Trust me. The early Hemis all weigh around 750 give or take. I got one haning on the engine stand.

Aside from that, 5/16 fuel line will support 600 HP. It's not the size, but the volume of fuel delivered. As long as you have an adequate pump, you will have zero issues.
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What he said. I had a 1972 Duster with a 440 that dynoed at 557 h.p. and I ran a carter high volume fuel pump with stock 5/16" fuel lines 750 dbl. Pumper and never had a fuel delivery problem.
 
Use a 3" line and get the extra benefit of having a few extra gallons of storage capacity!:banghead:
 
My 2 cent input. You will be fine with the 5/16ths line with your intended usage of the car. If your really serious about upgrading to a fuel injection system in the future I would contact the manufacturers of the various systems your considering and get a consensus opinion on what they recommend.
 
I run a -10 or 5/8 feed and return to the front of the car at 28-30 psi. The bypass regulator up front drops it down to a carb friendly 6 lbs. The trunk mounted fuel pump itself has a -8 bypass directly back to the tank too. Helps keep the 1 3/4 horsepower pump cooler at low fuel flows. It's feed by a -12 pick-up in a 30 gallon custom stainless, baffled tank that fits right into stock mounts of my 1970 E-body.

It feeds a 720 hp 493" sixpack, but it's pretty loud I spite of my attempts to get the sound down and out of the cockpit.

This winter, I'm going to switch over to the new Walboro OEM style in-tank high volume EFI pumps with a Radium Engineering surge tank ( the in-tank pump fills the surge tank and free fllows back to the main fuel tank at near "0" psi, but with very high volume) with another internal Walbro EFI pump inside the surge tank with bypass regulator mounted next to the it bypasses back to the surge tank to drop the pressure for the fuel feed to the front of the car to only 28-30 psi. The current bypass regulator up front is already seeing that pressure from my existing system and it can easily drop it down to a carb friendly 6 psi. It also bypasses the fuel back to the surge tank.

This system virtually eliminates any air induction into the pressure side of the fuel system even when the fuel level is low on a road course.

My current system can't do that. It's designed for straight line acceleration. It works very well for that though!
 
I got my advise from one of the best in the business and I took it.
spend the extra few pennies and install 1/2 inch.
cheaper to go faster.
 
65 Dartman said:
I wouldn't either; however, the guy I got it from (a Mopar buddy), installed a brand new fuel line back in the late 90s when he was working on the car and it's never had fuel run through it!.
Click to expand...

But time takes it's toll with condensation/rust etc!
 
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