holley carb help,transition/stage

Oldmanmopar said

Check the power valve 1/2 the vacuum reading is the number. Most of the carbs come with a 6.5 Once you go to a larger cam you need to go to a lower number. I am using a 3.5 and I am a little rich. I need a 2.5- 3.0

Does the carb have removable air bleeds. Smaller is more fuel larger will be less

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OMM, setting power valve opening by 1/2 of idle vacuum is wrong. It was wrong from the beginning and it’s wrong now and it will be wrong forever.

You never EVER set power valve opening by idle vacuum.

OP, if you are going to run a power valve, then you set the opening point a couple of numbers lower than cruise vacuum.

I would suppose for a foot brake drag car if there is a chance (and it’s a slim chance) that the power valve opens while you are staged, you could open the power valve later, but you’d need to put a vacuum gauge on there and measure vacuum while you’re foot braking it.

I’m not sure how, with the engine is loaded while foot braking that the vacuum would below enough to open the power valve even if out had a 10.5 PV in there. And that assumes that opening the power valve while foot braking doesn’t need to happen. It may need to open, it may not. You just need to get a vacuum gauge on it and see what it says, and then open the power valve accordingly.