1995 z240 Over Reving with 28p Prop
 

I recently purchased a 1995 Z240 with a "Performance Tuned" 7.4L Merc and a Bravo III (2.00R) outdrive . The boat came with a pair of Quicksilver 28P 3 blade props (48-823669 A6 inner; 48-823670 A6 outer). The boat is quick out of the hole and planes easily, but the top speed is roughly 38mph @4700 rpm. It can rev as high as 5300+ rpm and will continue to increase in speed up to roughly 42mph (I've only pushed it past 4900 once and only for a few seconds).

It never feels like its free wheeling, sucking air, slipping etc. but surely something is amiss as I would expect the top speed to be closer to 50+ @4700.

Any suggestions, thoughts, etc. are greatly appreciated.