can i use a 5/16 fuel sending unit on my 440 69 charger??

[itchyballs]

hey guys. can i run a 5/16 fuel sending unit for my 440 in my 69 charger? thanks!!

[bull]

Yes but 3/8 would be better.

[Big Lebowski]

No way 5/16 is for 383 2bbls & small blocks. 3/8 is a 440 HP line. If you had the 500 HP stroker, then I'd say get the new 1/2 version.

[dkn1997]

you could run that sending unit, you would just have to drill out the old nipple and solder in a bigger one with the corresponding hardline bent properly into the tank with mount for leveling switch and float and....and.....

better off buying a 3/8 unit.  I got mine from year one years ago.

[firefighter3931]

No way 5/16 is for 383 2bbls & small blocks. 3/8 is a 440 HP line. If you had the 500 HP stroker, then I'd say get the new 1/2 version.

I'd have to disagree. A friend was running mid 10's with the factory 5/16 line and a HV mechanical pump. That engine made 560hp fwiw. Sure a 3/8 line is preferable but a 5/16 is more than capable as long as you're blow that power level.  One suggestion i will make is a good mechanical fuel pump. The Carter HV "street" pump works great and is rated at 6psi and flows 120gpm....plenty for a street/strip 440.

Ron

[8WHEELER]

Yep I would run 3/8 because you never know what you might do in the future. But a friend of mine
runs a 440 less built than mine, with 5/16 line, and it runs 12.80's all day long, stock pump as well.

Dan

[deputycrawford]

If you need to purchase a sending unit now then think of the future and buy the 1/2". I have one on  my 383 that runs 12's. it works great and I never have to worry that I'll run lean through the traps. But if you think about it, all stock 440's came with 3/8". I would at least think of buying the 3/8" system. My 383 doesn't keep the 6 PSI through the traps. Its has more like 4 PSI. If my 383 uses that much at 6500 RPMs, just think what a mild 440 uses. If the lines too big, the pump just doesn't use it. If the lines too small, the engine runs too lean and a piston melts. Its up to you.

[Badbob]

I run 12.7s  with a stock pump and 5/16" lines.

[BigBlockSam]

i just replaced mine in my 68 r/t . it was 5/16  from the factory with the 440 motor. i have a sixpack on this car and it has never suffered from the smaller line.

[TylerCharger69]

Has anybody considered a possible vapor lock issue  with the smaller fuel line?.....I don't see why it wouldn't work.   I actually changed my steel lines to regular braided rubber ones and it's 5/16 and had no problems.  When I first bought the car, the steel line was rotted away in many places, and was easier to deal with with the rubber braided line, not to mention in case of a leak, it's an easier repair.   But....as far as your question...it'll work, but I would use the 3/8 version as that was used on 440 HP cars.   I would at the very least, upgrade to a stronger mechanical fuel pump   putting out 6 psi  as opposed to the 4 psi.  But as long as you know how much gas you have....who cares?....lol......just kidding           Ace Tyler

[Steve P.]

FWIW::      One of the major faults we found on the fuel system of VegasMikes 68' Charger was the use of a fluid filled fuel gauge under the hood. These gauges can give a false reading as the temperature rises. Mike would set the regulator cold and by the time the engine was up to normal operating temps. the gauge was showing a major loss in pressure. 2 such gauges were tried with the same results. Then the good people at BG told me about the problem and Mike went to a NON fluid filled gauge. 7 PSI all day long with the new  gauge..

[BigBlockSam]

but I would use the 3/8 version as that was used on 440 HP cars 

thats not  true. my 68 r/t has a 440 hp motor and it had the smaller line from the factory so does my 70 r/t. the larger line was used on hemi cars and sixpack cars. Rene

[TylerCharger69]

correct...i should have been more specific i guess.  Dual quad cars as well.......

[BrianShaughnessy]

FWIW::      One of the major faults we found on the fuel system of VegasMikes 68' Charger was the use of a fluid filled fuel gauge under the hood. These gauges can give a false reading as the temperature rises. Mike would set the regulator cold and by the time the engine was up to normal operating temps. the gauge was showing a major loss in pressure. 2 such gauges were tried with the same results. Then the good people at BG told me about the problem and Mike went to a NON fluid filled gauge. 7 PSI all day long with the new  gauge..

I had a Russell fluid fileld guage and it did the same thing.  Went back to the old stuff.

But either way...   I put in a 3/8" stainless line to replace a 30+ year old 5/16 rustyazz POS.    The price differential is minimal considering between the 5/16 and 3/8 to bother sticking with the smaller stuff.    I've never had a factory 3/8 line on any of my 69's over the years and they werel XS29L's.  Go figure.   

[Steve P.]

My 65' Coronet came stock with a 5/16" feed,  no return line and a venting cap that tends to dump gas when you nail it.  When the day finally comes that I get to work on that end of the car, it will have a 3/8" feed with a 1/2" return line and a separate vent working off the filler tube. Then I am hoping to get my hands on a gas cap that will not spill all over the place.. 

[deputycrawford]

Steve P. I know your idea but don't you mean a 3/8' feed line and a 1/4' return? That will help keep the pressure up to snuff at all fuel demands (full throttle).

[Steve P.]

Nope....     3/8" from the tank.  ( Maybe even 1/2 inch from the tank to the pump if I go electric). Then 3/8" forward to the carb. Return line from the carb will be 1/2"...

Every engine requires a certain amount of fuel supply of both volume and pressure. The one thing you don't want to do is have much pressure in a return line.  That is the reason for the larger return line than the pressure line. Even if the regulator fails the pressure will drop.

On every high pressure to low pressure system you see it is exactly this way. Your power steering. Your air conditioning and yes, even your toilet...    This is the propper way to do it. Some systems do not require return lines. My STOCK 65' Coronet 500 never had one. That doesn't mean it would not do better WITH ONE!! 

Todays fuel pumps are a bit more stout than the stocker of 65'. As are the disc brakes, computer controls and so on.

I figure it's better to have too much insurance than not enough..

[8WHEELER]

  but I would use the 3/8 version as that was used on 440 HP cars 

thats not  true. my 68 r/t has a 440 hp motor and it had the smaller line from the factory so does my 70 r/t. the larger line was used on hemi cars and sixpack cars. Rene

68-70 440 hp, 440-6pk & Hemi cars came standard with 3/8 fuel line and 5/16 return line. All of the books back up
this fact. Every 68 440 R/T Charger I have owned, worked on or seen came with 3/8 fuel line. I have never seen
5/16 on any 68-70 R/T car. I am not saying there was not some made with 5/16 but as a rule they are 3/8.

Dan

[TylerCharger69]

okay..im lost.....which return line are you referring to??  I have the one from the tank to the pump...and one from the pump to the carb....my sending unit only has one tube on it, and there is no vapor canister.....is there something missing that i dont know about?.....car runs fine by the way.....

[BigBlockSam]

Dan
  the rule is not 3/8 for 440 hp motors. they came with 5/16 all the books say only hemi and 6 pack cars got the 3/8. yes some might have 3/8 if they ran out of 5/16 i'm sure they stuck a 3/8's in there at the factory, i've changed 4 senders in the last 2 yrs seems every charger i buy the gauge don't work 3 were r/t 's . they all hd 5/16 line. when i ordered them they asked me if it was a 6 pack car or a hemi car, i said no. they sent me a 5/16. they were rite and what return line are you talking about on the 68-69 charger?  Rene

[Steve P.]

okay..im lost.....which return line are you referring to?? I have the one from the tank to the pump...and one from the pump to the carb....my sending unit only has one tube on it, and there is no vapor canister.....is there something missing that i dont know about?.....car runs fine by the way.....

Tyler, your not lost.. You are right. Your car probably does not have a return line. Nor does mine. Nor did many of our beloved Mopars when they came from the factory. Many of them still DO NOT.. Some that HAVE them do NOT need them.. SOME DO.....

Most times people add a return line to their system is for a hi performance fuel system. ALL fuel injection systems MUST HAVE a return line. Most Vapor lock problems are fixed with return lines by keeping the fuel moving. This in turn helps to keep it cooler.

There is more to it than this and I am not much of a guru, BUT, with all the reading I did on the subject and the very small amount of cost for the DIYs, I am more than sold.

You can check out plumbing fuel systems on site like BG. GOOGLE will get you there quick..

[BrianShaughnessy]

The 1/4" return line is really only used for a factory vapor separator.   I'm sure 6T9 Chris has a good pic of his somewhere.   This is generally a hemi / 6 pack item.  There is a fuel filter with a return outlet that was used on some later models but not the classic years.

I bought a repro separator and rigged it in and the car wouldn't run for sh8t.   Turns out there's supposed to be a small restictor in the return that these repros may be lacking.   I was only getting about 2 psi fuel pressure out of a carter pump that has to be turned down with a regulator otherwise.

[Steve P.]

Brian makes a good point.  As I said, the return line I plan on using IS for hi performance. It will be used (AFTER) A REGULATOR that is designed to only return unused fuel to the tank.


Quick example: VegasMikes 68' Charger has a Holley BLUE pump. This pump moves 110 GPH @14 PSI. On a normal non-by-pass, regulator you would increase the load on the pump @ 7 PSI. Using a by-pass regulator and a larger line to return than to feed you will circulate unnecessary fuel back to the tank and not over work or over heat your pump. Also takes some of the residual heat out that is picked up from under the hood..

[8WHEELER]

This is an original 68 440 HP Charger, like all of the others I have had has a 3/8 fuel line and a 5/16 return.
The fuel vapor return line simply goes from the fuel vapor seporator shown on the engine below to the
sending unit,  Hi again Chris 

Dan

[BigBlockSam]

i've never seen that canister on a 68. i'm gonna go look at a 68 r/t and a 69 r/t this week. i will look down at the fuel pump and see if theres a canister like that on them.  any body out there with 68 and 69 440 cars, do you have that canister to? the clean air act was passed by the goverment in 1969 thats why 70 chargers have the Evaporative Emission Control (EEC) , Rene