02-18-2017, 07:42 AM
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CC Member
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Join Date: Apr 2009
Location: Bethesda,
MD
Cobra Make, Engine: CSX 6022, navy blue, period correct 427 SO
Posts: 2,154
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Quote:
Originally Posted by patrickt
Vacuum secondaries have nothing to do with manifold vacuum. They run off of venturi vacuum, which is related to the velocity of the air/fuel mixture down through the carb. A big cam with low manifold vacuum will do just fine with a vacuum secondary carb. If your engine builder, or engine tuner, doesn't understand the difference between the two then you shouldn't let him even look at your engine.  |
You can test this with an air compressor. Direct air past the venturi in the primary to simulate vacuum load. Secondaries will open if you do it right.
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