What year did they quit bulding graymarine engines?

Question

chrysler graymarine was a flat head 6 cylender motor made for boats

Answer 1

they didn't  grey marine diesels were built by general motors in factories all over the world

Answer 2

I dont know for sure...there is very little info on the web about these things.  I have a 1963 Gray engine (Fireball 160 - all aluminum Buick V-8), but I dont know how much longer they made it.

There is an outfit by the name of Duby Auto & Marine, 716 694 0922, that knows everything about these motors and can get all of the parts that you would like need for a rebuild.