Edlebrock Carburetor Fuel Pressure

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65 Dartman

65 Dartman

1 of None 65 Dart Sedan Delivery
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I have a 650 CFM Edelbrock AVS carb I bought brand new in 1984 and ran it on a slant for a couple of years. I’m thinking about using it on my 66 273/235 in my Dart. What range of fuel pressure on an electric in-tank pump would be suitable for this style carb?
 
65 Dartman said:
I have a 650 CFM Edelbrock AVS carb I bought brand new in 1984 and ran it on a slant for a couple of years. I’m thinking about using it on my 66 273/235 in my Dart. What range of fuel pressure on an electric in-tank pump would be suitable for this style carb?
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About 5#. Check it and use a regulator.
 
The Carter 4070 is an external pump, not in-tank.
The E carbs are calibrated with pressure being 5.5 psi. The fuel system is a direct copy of the original Carter AFB/AVS design, which can run with 10 psi. Changing both/either the needle & seat size or fuel pressure changes the fuel level in the bowl. If more pressure is used, the fuel level should be lowered slightly. Carter published graphs that cover this.

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Since I have decided to go with a carb instead of a TBI FI - the horror stories on both the Holley and FiTechI FB groups outweighed the success stories. I pulled the Holley FI pump/sending unit assembly from my tank yesterday. This unit is a direct drop-in for 63-76 A Bodies. By the numbers on the pump it was a 58PSI Walbro pump. Walbro does have a low pressure (12 PSI) in tank pump. So doing more research through Summit i found a 6PSI in tank pump from Agility Auto Parts that likely would be just what the Edlebrock could use. Doing some more research I found this pump is designed for some Ford applications. They (Agility) has a bunch of cross references for different pumps - for example, the Carter in tank P60293 and P74067, both of which Summit sells. These cross reference to being used by Ford/GM vehicles. However, Summit doesn’t list the PSI numbers for either pump. Carter does show each has a minimum pressure of 3PSI but not maximum. Guess I’ll be on the phone Monday for more info.
 
65 Dartman said:
Since I have decided to go with a carb instead of a TBI FI - the horror stories on both the Holley and FiTechI FB groups outweighed the success stories. I pulled the Holley FI pump/sending unit assembly from my tank yesterday. This unit is a direct drop-in for 63-76 A Bodies. By the numbers on the pump it was a 58PSI Walbro pump. Walbro does have a low pressure (12 PSI) in tank pump. So doing more research through Summit i found a 6PSI in tank pump from Agility Auto Parts that likely would be just what the Edlebrock could use. Doing some more research I found this pump is designed for some Ford applications. They (Agility) has a bunch of cross references for different pumps - for example, the Carter in tank P60293 and P74067, both of which Summit sells. These cross reference to being used by Ford/GM vehicles. However, Summit doesn’t list the PSI numbers for either pump. Carter does show each has a minimum pressure of 3PSI but not maximum. Guess I’ll be on the phone Monday for more info.
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Been looking to do this also. Could 12 psi could easily be dropped to 5 or 6 with a standard Holley regulator? Tanks, inc has a return regulator for use from 58 to a carb.
 
66fs said:
Been looking to do this also. Could 12 psi could easily be dropped to 5 or 6 with a standard Holley regulator? Tanks, inc has a return regulator for use from 58 to a carb.
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If you are going to do all the work to do an electric pump I’d use a return regulator and not a dead head regulator.

No matter what, no regulator would say Holley on it.
 
I think that Walbro pump could be dropped sufficiently enough for a carb to function without issues.

I bought a Holley regulator years ago to drop the pressure from a mechanical fuel pump to low enough for a trio of SU Carbs which require a low pressure of 2 or 3PSI to function without flooding The SUs were sold but still have the regulator

Right now I am leaning towards the Agility fuel pump with it’s max pressure of 6PSI unless the Carter 74067 has a similar max pressure. The Carter also has the hydramax filter similar to the Holley in-tank system
 
Once you put the regulator and pump on, take it for a shake down cruise. If you can, put a pressure gauge where you can see it. Try it normal street driving and at highway speeds to see if the pressure goes up or down. Once you know the operating pressure range, adjust it accordingly, no more than 6-7 psi at the operating range. You don't want to flood it, but you also don't want it running lean at highway speeds.
 
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