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Old 12-05-2019, 03:42 PM
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Quote:
Originally Posted by FredG View Post
The Holley carb that came with my 427r ran the best when brought back to factory specs. Having the wrong power valve or one that stuck open will definitely affect performance when accelerating and the vacuum drops. Open throttle is a different story but the vacuum will have to catch up to the throttle and that is where the power valve comes in till it does. Wrong jets are another issue.

Fred
Your carb must have been a long way out.

A power valve stuck open will affect fuel economy, but not outright power.

The only way that can happen is if the diaphragm has hardened from lack of use. A ruptured diaphragm becomes a fuel leak into the PV cavity, which is then a fuel leak into the manifold vacuum port of the throttle body.

Manifold vacuum responds in inverse proportion to throttle movement, so vacuum does not need to "catch up" with throttle movement.

Gary
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