205 HP according to Merc, but 230 according to previous owner. The engine is a Mercruiser 4.3LX (4 bbl). Not sure if any and what mods may have been made.
17 - 19 upper gears before serial number K999999 gives a total ratio of 1.84 to 1 and after that a total ratio of 1.81 to 1 because of differant lower unit gear ratio.
Look at the picture below. Not only are the numbers on the decal, but they are stamped on the upper casting under the decal in the same approx. possition. That will tell you what it was when it was new. But if anyone has rebuilt the drive or used different gears in that housing, all bets are off. And, it is an 88 drive.