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Old 09-15-2021, 11:28 AM
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NeighborsComplaint NeighborsComplaint is offline
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Join Date: Aug 2009
Location: Elgin
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Quote:
Originally Posted by Kenth View Post
You can not plug the tank vent and expect the fuel to flow properly.
Fix the tank ventilation factory style and add an electric fuel pump (Carter P4594) on floor pan above rearend. Remove the mechanical fuel pump and cover the hole with a CBB plate.
Job done.

FWIW
I installed the 1970 (pre-emissions) vent and filter system which uses 2 vent lines ('70 tank had only 2 vents) and capped the 3rd, unused vent off. '71's used all 3 vents but had a closed vapor system with charcoal filter, vapor return line and an accumulator all tied into the vacuum system.

The '70 vent filter is mounted high on the frame and just vents to atmosphere. My '71 frame still had the provisions and pre-drilled holes to mount the filter as a carryover from '70. The '70 - 2 vent system is just as capable a system for venting the tank.

As-mentioned, I already have a good electric fuel pump wired to a switch for intermittent use mounted ahead of the tank with the inlet below bottom of the tank. What you suggest is just the same style pump as I have but you suggest mounting in the wrong location. Rotary vane pumps, like the Carter and my Holley are made for gravity feed and not intended to lift fuel up from below. The inlet should always be below the level of the fuel to work efficiently and not cavitate.

While removing the mechanical pump would eliminate any tendency for vapor lock, the constant noise of the electric pump is not for me. That is why I installed it on a switch and use only when needed. When I felt the onset of vapor lock I turn it on. In cooler weather it is not needed, the car runs the same with or without the electric pump on. The mechanical pump is more than adequate without the whine.

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Last edited by NeighborsComplaint; 09-15-2021 at 11:39 AM.