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Old 01-02-2018, 09:03 AM
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Tom Vaught Tom Vaught is offline
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Join Date: Dec 2001
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Today I am going to post a couple of pictures of a 3 circuit Dominator Metering Block.

Years ago Holley had 2 Circuit Metering Block Dominators and they ran fine. Then some people decided that if two Circuits are good, then three Circuits have to be better, Right? Marketing People. And they were right, Holley sold a crap load of Three Circuit Holley Carbs. And in many cases the three Circuit carbs gave the slow guys bragging rights at the Dairy Queen with their Dual Dominators on their Supercharged "Sticking out of the Hood" Chebbys. And they never had issues with the carbs because they never really exceeded the Air/Fuel demand of the Carbs.

But now you take the Real Race Guy.
At some point he is going to make big power with his Single Dominator Carb on his 500+ cid engine. At that point he will find out that the carb basically stops flowing any additional fuel thru the jets at about a #99 Jet Size. But this was years ago, before all of the Dominator Modifiers got involved. So what was the issue here? Hey, We bought the 3 Circuit Carb and 3 circuits are always better vs 2 circuits right?

Well people I will post up a couple of Pictures of why the Engine Performance "Flat Lined" purely due to the 3 circuit design.

a) All carbs have a Idle Circuit and a Main Circuit in the metering Block and some carbs have a Third Circuit called the Intermediate Circuit which is supposed to help on street cars with Dominator Carbs on them. And it does help on the lower powered engines.

But when you get into the higher powered engines you need more fuel flow thru the metering blocks main circuit.

So here are the Pictures. (Of a "cutaway" Main Circuit on a 3 Circuit Carb.) See anything wrong here?

Tom V.
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