Power Valve Restrictor Channel Tuning

Thank you.

Yeah I been reading though David Vizards Holley Super Tuning book. He goes into how the high speed air bleeds can be used to shape the curve in the upper rpm range.

I think I found what I need finally! On summit I was able to find from Quick fuel idle Feed Restrictors all 6-32. So you can't find anything listed as PVCR except for blanks but if you search for idle feed trstrictors you can find a lot of sizes that seem to cover the right range and from what I understand those should screw right in.
Not an easy thing to find. I asked for summit tech support and the guy gets on the phone and tells me that I don't understand how it works and I don't want to restrict the power valve and then goes into how the power valve works.

A little humility is always a good thing. You never know when a subject will come up that you don't know anything about.

Mattax said

Air bleeds are for getting the AFR so its flat through the top of the run. They also can effect how smoothly the main circuit initiates but that's secondary.

The power valve channel restrictors control the amount of enrichment fuel. Think of them as an additional main jet.
If your carb's metering blocks have threaded PVCRs, then BLP or Quick Fuel or Proform should have them.
Yes the alternative is to drill your own.
There are other work arounds. To my surprise I have found the PCVR on an old holley was exactly the right size. Of the two best jettings on the chassis dyno, the leaner was just past what the engine would tolerate at highway speeds. That worked out well 'cause at the track I would have chosen the richer of the two anyway.

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