I have owned my 88' 201 since 1996. Bought it from the original owner with 190 hrs. on it. I, like many on here believed it was a mid-fifties boat until I borrowed a friends GPS and averaged btw 48-50 with a couple of people and half tank of gas. What can you expect, however, from a heavy boat with 230 php. I bought a 23" prop thinking this would get me more speed, but gave me nothing but poor acceleration, low top speed rpms and a lot of bowrise. This boat stock is meant for a 19", maybe a 21" stainless if you have a strong motor. Four Winns has archives on all their older boats including top speed ranges. Only two boats came from the factory capable of hitting 60mph: 502 201 and the twin engine 241 and this was in ideal conditions. Most are high forties, low to mid fifties including all the big block 211's.
If you are going to keep the boat and want speed, you will have to do what I did after the GPS incident and prop testing: pull the motor and go to town!! Took it to a machine shop, had them rebuild the lower end, then I put new pistons, hotter cam, SR torquer heads, edelbrock intake and then took it to a dynoshop and tuned it on the stand. I read every Hotboat and Powerboat tech article for 2 years to figure out what to buy. Made 385 hp for about $3000 in money. Best investment I ever made. Six years later and I still hit low sixties everytime I pin the throttle. I consistently run with the newer big block single engine 25 fters. Baja, Formula, you name it. Some I even beat. I pull btw 4700 and 5000 w/ a 14.25 23P for speed runs. OMC outdrive has been bulletproof after two early on rebuilds (before I rebuilt the motor). Keep the outdrive full of amsoil and the revs below 5000 and all is well.
In the vid I am running a 21 merc prop nipping 60...
http://www.facebook.com/video/video.php?v=1029206062973&saved
Plus, with a used boat, you really never truly know what has been done to it unless you get it from the original owner. He checked the block #, and low and behold it was a 502...