Need OMC Upper Half of outdrive

I have a 1983 Galaxy 17 ft bo

I have a 1983 Galaxy 17 ft boat with a 4 cyl and omc outdrive.The previous owner messed up the upper half of the outdrive. He had it replaced with a used unit that is geared wrong for the boat.I was told I need a unit with 17/21 gears. Is this right?I started pulling it apart and 1 of the gears has 16 teeth [cant see the other gear yet]At 4400 rpm it will only run about 30 mph.[just guessing]I do know its way to slow for this boat.Where can I get a used unit I need reasonable?Have already had the motor rebuilt[was blown when i got it from over reving]and dont want to put a fortune in it.The unit I have is in perfect condition just geared wrong.[maybe can do some trading???] Any help would be great. Thanks Tim Higgins

You need an upper with 21:18

You need an upper with 21:18 ratio. I have some. See my website at www.mmmarinesalvage.com. or call me at 603-279-5041. George

Thanks for the info George. I

Thanks for the info George. I'm confused though. Anothor mechanic said I needed a 21/17 upper.I'm not doughting your word but I want to be sure.Please double check and I'll get the other mech to do the same.I'm interested in your parts.How much do you get for a used upper?Thanks again for your help. Tim Higgins