My GPS (memory) recorded an absolute top speed for my 23SE/F225 as 45.4 mph. I am sure that was very light and trimmed all the way out in flat water.
Normally loaded my boat hits 43/44 @ 5800 rpm, WOT (but I very rarely run WOT; and there is a shocking fuel burn penalty to doing so).
I can get you more precise information when I splash the boat in a few weeks. Generally, I cruise in the 30mph range at a few tics above 4000 rpm. My best recollection is that fuel burn is about 8 gph at that cruise rpm. I am proped with an original SWS 19 pitch (and considering dropping down to a 17).
Paul