What year lower units will fit my 1971?

[Bearcamp]

I have a 1971 Johnson 20 hp and was wondering what all year and hp. lower units will fit mine. I'm talking will some 5 hp. and some 1958s or whatever will work?

 

[R.Johnson]

Re: What year lower units will fit my 1971?

This is just a guess here, but I would say any 18, 20, 25 HP case from about l956 to 1976, or7. I put a 1975, 25HP case on my son's 1957 18. The 25 just had a slightly higher gear ratio.