I have a 1999 450 voyager. Flawless condition, low hours new bottom job no problems. The top speed is 20 mph. I've had it over a year and it has never got over 20. Engines are 450 cummins. I have talked to other owners and the factory. They claim speeds of 27 to 30. I can't get close. The engines are reaching their rated speed of 2650 at wot. This was the first 450 voyager built. Carver said the test was done with this boat. 29 mph when tested. The only thing left I can think of is the trim tabs have never worked. I can't imaging the tabs could make much of a difference as I've never used them on any other boat I've had but I don't know. Any thoughts would be appreciated. If there are any other 450 owners out there what is your top speed and do the tabs make a difference?