TOPIC: interchangable parts - merc 500

I have a 1965,1966, and a 1968 merc 500, will the lower units from
the older ones fit the 1968 or vise versa?
the tell tail on my 1966 merc 500 is clogged, any ideas on how to open this up , the motor cools fine. I have tied to ream it out with a wire,compressed air and lime away.

yes they will. drill and tap on top of the water jacket and put in a new tell tale.

thank you, this motor (1966 merc 500) has a screw plug already on top, can I just put in a right angle fitting and hook up a rubber line to it. I would imagine it has the same water pressure as the one down below.

As they say on storage wars, YUUUUP!!!!!