Somewhere on the bell housing there should be (maybe) 1 or 2 little circle(s) cast into the housing. The circle(s) will maybe have a combination of: center dividing line, dots, a number. Very seldom have I ever tried to decipher this type of code, but it can be done. Someone else may be more familiar with this type of code.
Someone else needs to jump in here.
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Tom Parsons