Fuel Pump Question

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Pale340

Pale340

Pale340
Joined
Jun 24, 2010
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Location
Huntsville, AL
Hey All,
So, for some reason, unbeknownst to me, I ordered 3/8 fuel line from the tank to the pump. My car is a 73 340 Dart Sport. I really do not want to send it back as I bought new clips, hose kits, etc. for the 3/8 line, and I just do not want to go through the hassle packaging everything up and paying for return shipping. My future plans for the car, after I hit the show circuit for a couple of years, is to 6 pack it so the 3/8 line is good. I have found the correct sending unit that has 3/8 out and 1/4 return, but I want a fuel pump that looks stock but has the 3/8 inlet. Will it matter if it is 5/16 up to the carb? I think I found a Carter that is 3/8 inlet and 5/16 outlet to the carb. Is the 5/16 the correct size line from the factory. I am trying restore this car back to factory looking as much as possible. I know the 3/8 to the pump is not factory and there are a few other things that are not factory as well. However, I am still trying to stay as close in appearance as possible. Any help on where to find a factory looking small block fuel pump with a 3/8 inlet would be appreciated. Thanks.
 
Based on your information I don't see a problem with your setup. The 3/8 line will have more volume than the 5/16. If you're feeding the carb from the fuel pump with a 5/16 line on a NA engine it won't be an issue. Just make sure the fuel pressure is regulated properly for your carburetor. 65'
 
Some folks mistakenly think that partly large, and partly small line restricts the flow to the "smallest" standard. This is not true for two reasons

1....In this case the large line is on the suction/ low pressure side of the pump. That is where larger line would do the most good, as restrictions in the low pressure side ESPECIALLY in a suction line make much more difference than on the higher pressure outlet side

2....The smaller line is not very long. FRICTION is what matters there, as the line is much shorter, as well as higher pressure, so the effect will be minimal
 
Run it. As long as the fuel in your line flows laminar your good to go. You like that big word? lol
 
So the Carter pump I found turns out to be a 5/16 inlet and outlet. Anyone know of a 3/8 inlet and 5/16 outlet that looks like the original? If so, let me know please. Thanks.
 
Pale340 said:
So the Carter pump I found turns out to be a 5/16 inlet and outlet. Anyone know of a 3/8 inlet and 5/16 outlet that looks like the original? If so, let me know please. Thanks.
Click to expand...
Get a 3/8 to 5/16 adapter if you cant find the right pump
 
So Inline tube is taking back the 3/8 and exchanging it for the 5/16. They sent me a FedEx return label and said if I order the 5/16 then they will only charge a 10% restocking fee as opposed to the normal 20%. It is worth it to me since it was my mistake ordering the 3/8 instead of the 5/16. Lesson learned for sure here. Pay attention.
 
my advice would be to get the pump that works for the final goals of the car, no point in buying it twice

personally, i would go with the carter M6270

it comes with 1/4 NPT fittings, so you can run 3/8 in, 5/16 out and when you're ready to go with the sixpack, you can change the output to 3/8 as well
 
diymirage said:
my advice would be to get the pump that works for the final goals of the car, no point in buying it twice

personally, i would go with the carter M6270

it comes with 1/4 NPT fittings, so you can run 3/8 in, 5/16 out and when you're ready to go with the sixpack, you can change the output to 3/8 as well
Click to expand...

Agree
 
I run a 3/8" line from the tank to the fuel pump, you could have gotten a flared 5/16" - 3/8" adapter at a Hardware or Automotive store anywhere. When you go to your six-pack set up (mine is) it's still going to be 5/16" from the pump up to carbs, factory, unless you change all of it.
 
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