Year range for square shift shaft lower units?

[rjb75]

I have a 77 500/50, s/n 4805702. The PO gave me an extra lower unit which he says is good but it has a square shift shaft. Everything else looks to be the same on my working unit as this one but obviously I cannot use it as is if I have a problem. Can anyone tell me what year or s/n range this type of lower unit fits?

 

[Faztbullet]

Re: Year range for square shift shaft lower units?

Middle 60's

 

[rjb75]

Re: Year range for square shift shaft lower units?

Alrighty then-probably not going to be helpful to me so I'll sell it.