Help with prop and set up.

[496cubes]

Hello all. I have a 1975 steury 180-x with a 2004 evinrude 200 di. 6 inch hydro jack plate. Currently running 23 pitch 3 blade. Hitting rev limiter at 3/4 throttle so obviously bigger prop. But unsure of where to go. First run this past summer was with 14 inch bobs flats jack and chine walked at 5100 rpms scary bad at 72 mph GPS. That much setback pushed transom to far down in water and upon throttle down water came over transom. Put a 6 inch on and can't find a 27 to run again. (Borrowed prop later sold) hitting 64 at 6000 rpms I know to much. Any input would be great 270961270962270963270964