Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - vacuum secondary or douple pumper
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Old 01-30-2013, 07:53 AM
snakebit68 snakebit68 is offline
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Keep in mind that when under load your carb is dumping alot of fuel through the system, but your RPM's arent going to build fast enough to burn all that fuel when towing, resulting in poor fuel economy. I had a similar issue on one of my work trucks. We switched it over to an Edelbrock 750 with vacuum secondaries and increased our average fuel mileage by 2 MPG and it towed much smoother. Of course, to be honest, we may have gotten the same results by fine tuning the Holley 750 we had on it to begin with.
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