I am guessing you have an older EFI without the rev limiter. I have a 97 PanteraII DC with Merc200 EFI. I routinely turned 6150 rpm at wot with 25 old style Trophy. This was with manual jackplate untouched from the day I picked it up at the dealership. Actually, went to the factory and towed back to dealership for final rigging/prep.When I moved to a hydraulic jackplate this past year, at same engine height, jackplate was bigger than the CMC, so motor a little bit further away from transom. My rpms went to 63-6400 with water pressure of 12. Moved up to a 26 Trophy plus and now can get 58-6000 rpm with water psi at 14-15, two holes plugged.The older engines can handle a little higher rpm, but would still entertain ideas on what the other guys think also.Then again, maybe the jackplate is too high….Hope this helps.96 Eyra/12 Mercury 175 Pro XS with 2015 single axle trailer2017 Victory Gunner