Need help, difference between an '81 and an '84 35hp Johnson lower unit

Alright guys, I'm fixing my messed up lower unit in my '81 35hp Johnson. Gears and clutch dog are stripped. I just bought another lower unit and found out its one off an '84-97 unit. I tore the '84 apart and saw that the gears and clutch dog are different than the ones in my '81. Can I still use the '84 gears and clutch dog? What's the difference between the two? The housing are exactly the same as well as the other parts I see. Also, my '81 is a long shaft and the '84 is a short. Thanks! I can post some pics if needed.

After completely dismatling both lower units, I found out that Johnson changed the pinion gear, forward gear, reverse gear, clutch dog and cradle, and the prop shaft in '84. Just in case anyone else needs this info.

deep fried, I was wondering where you got off to. Never heard anything else after you went to piney last year.

hey steve, i've been lurking around here off and on here lately. Havent really been on the water much with other projects going on. Figured now is the time to try and get this ole' boat going so I can be ready for the spawn. Unfortunately I'm not making much headway, lol.