Trimming out on my 98' 222, 7.4MPI Bravo I
 

So I am a new owner of a 1998 222 Shabah that had only 78 original hours! Beautiful boat, but I haven't quite learned the tricks of trimming it out well yet. My last boat was a V-drive so trimming wasn't an issue. The boat has a 1.50 ratio Bravo I drive with a 23 P Mirage Plus ( 3 blade) prop, and the 7.4MPI motor. Based upon my research, this set up should deliver about 50 mph at 4500 RPM (which is a safe WOT in my opinion on a Big Block). However, I am only able to get up to 37-39 mph according to the GPS. Additionally, I am only able to get the trim to go to the halfway point before the prop seems to lose it's bite it the water and the engine revs up beyond my comfort level. I suspect that much of this is just my learning curve based on my lack of I/O experience so I am looking for a little advise.

Thanks,
Chris