Putting a CS prop on a fixed-gear bird will not get you any
appreciable speed.

The only thing it buys you is takeoff/climb performance, and unlikely
to have increased your legal gross weight any.

I never said that the prop did either of these things. What did change
things was putting a 180hp O-360 in the place of a 150hp O-320. The
extra 19hp at 65% power does in fact make it go faster. And the new
legal gross weight per the STC is now 2500.