Ok so for those of us who do not have or can afford to make dyno runs to adjust our power valves.

Is there a guideline for how many turns or portions thereof that equates to X RPM?

For example:
.5 Turn is approx X RPM
1 turn is approximately X RPM?
1.5 Turns is approx X

Thanks for the real information on the PV Jerry, lots of great insights.

I did not pay close attention to the actual RPM change per turn of the dial but my memory says it was about 500 to 600 RPM change per 1 turn of the dial.