How fast should I be going? I've got a 1993 20' Stingray 609 zpx with a Merc 4.3L LX Alpha One 180hp. Drive ratio is 1.84. Weight of the boat plus motor, fuel, gear, and myself is 2050 pounds (Boat and motor alone is 1575 pounds). At WOT I'm hitting 4800 rpms and GPS is tracking my speed at...