Carb decisions
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Freshman User
Joined: Mar 2001
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Carb decisions
What is your honest opinion on Holley Double-pumper carbs. I do a little off-roading, but not a heck of a lot. Mainly mud. Are there any drawbacks to the mechanical secondaries? what about the power valves?
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Joined: Jan 2001
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From: Virginia
Carb decisions
Double pumpers are not recommended for heavy vehicles. A large truck with a large tire will not have the response needed to take that large gulp of air and fuel when you mash the gas. It will have a stumble or bog that will be hard to tune out. Everybody likes to slam the holley power valve, but FORD carbs had them too, and unless something is wrong to cause a backfire, they usually don't give any trouble. Every carb has a power system of some sort, holley like Ford used a diaphram that can get a hole blown in it. I've also heard good things about the edelbrock/carter carbs too, which have a mechanical system for the "power valve".
Junior User
Joined: Feb 2001
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Carb decisions
I have a Holley 600 vac. sec. on my Bronco and I have a 650 double pumper on my Mustang. I would not put the double on my truck. It even has a tendency to bog in a light car like mine so a truck would be really bad. You have to have the engine in a very tight powerband or it will bog. The vacuum carb is great for a truck because the secondaries don't open until the engine needs them. So it remains a 2 bbl until it gets into the power range for all 4 barrels. I have tuned both carbs to where they run beautifully. The Bronco will almost run upside down. I like Holleys because of the adjustability and availability of parts.
If you just want to stick something on and never mess with it then you may like the Carter/Edelbrock. The Holley can do the same thing but if you may want to fine tune it or be able to adjust it to future mods, the Holley is A LOT easier to adjust and tune.
If you just want to stick something on and never mess with it then you may like the Carter/Edelbrock. The Holley can do the same thing but if you may want to fine tune it or be able to adjust it to future mods, the Holley is A LOT easier to adjust and tune.
