That's interesting! What is your WOT RPM's? What should it be for my boat? How do I know if I'm properly propped?Comparing to the old prop is tough, for several reasons: the old one is probably hand made, and therefore less precise. It could have been rebuilt or otherwise modified in its life, and its overall blade area (% of the overall area within a circle that is taken up with blades) is probably much less than a modern CNC Acme prop. My boat had an OJ 14x16 4 blade, hand made prop that had been rebuilt several times. The measured diameter was actually under 13" when I took it off. I put on an Acme 1868, smaller in every dimension except blade area - 12.5 x 14.25 4 blade .075 cup - and it turned almost exactly the same WOT RPM, although much more smoothly, and the overall feel and throttle response was much better. With a 310hp engine and a 1.23:1 transmission, a 422 seemed like the right prop on paper, but it was way under WOT by 400-600 RPM.
The only way to be 100% sure about getting the right one is to try it with your individual boat, using it the way you expect to normally use it. A lot of places will let you try a prop and exchange it, provided it comes back undamaged.