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Thread: Secondary Power Valve Question

  1. #1

    Default Secondary Power Valve Question

    Got me a 4779-6 Holley 750 mechanical secondary with 4 corner idle adjustment. Popped the bowls off and noticed the secondary metering block doesn't have a power valve, and is plugged off. Pretty sure it came stock like that. It's going to be street driven more than raced, but will see some track time. Do you all recommend installing a power valve in the back, or just leave it plugged? It has the stock 80 jets in the rear, but the fronts were changed out from 71s to 67s.

  2. #2


    After a lot of reading, I realized this was a silly question. From what I've read, a metering block that doesn't come with a power valve from the factory, will have to be modified if you decided to run one (drilling & stuff). Anyways, I left it blocked off and went back with stock jets. I fully rebuilt the carb and put on my 406. Finally got time to get it fired up today and tinker with the 4 corner idle. Have to say, I really like how that works. Gonna get me a vacuum gauge later on a dial it in better, but for now I'm happy with it. Looking forward to some track time later this year. :-)

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