GPS'd, I wouldn't expect to go over 60mph. I was always told the Bermudian P16's ran better with the smaller 70hp motors (modded of course) and with them, on GPS, 58mph was the fastest I've heard. The 90s never ran as good as the smaller/lighter 70s. The 66mph somebody else posted a while back just isn't true and his prop setup is waaaay off. Get a GPS in the boat and see what speeds you're hitting right now...my guess is if your gauge says low 50s you will be lucky do doing a true 50. But that's just IMO.
And do you happen to know who owns the baby blue P16 that raced a few years ago? I really want to buy it and if I can find the owner I'll make an offer asap and hopefully be racing against you next season...