1969 350/350 alternator Pulley
In previous question and Joe Lucia response, I have a question on the correct configuration of the pulley for the alternator. According to Joe, the pulley should be a 1970831 which is a machined deep groove pulley. Seem to be hard to find and pricey on Ebay. My question, did the original pulley have a slot machined in it for a key or was there only a hole in the center. Want to be sure and get a correct one. Thanks for any comments or pictures of originals.
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Re: 1969 350/350 alternator Pulley
Steve-----
I believe the GM #1970831 did have the keyway but I'm not sure. The GM #1970831 was discontinued in November, 1984 and replaced by the GM #3844100, a pulley that dated back to 1964. I think (but don't know, for sure) that the only difference between the 1970831 and the 3844100 is that the former has the keyway and the latter does not.
It's really kind of academic. For a Corvette alternator the keyway is not required and it is, thus, superfluous. Once installed on the alternator with the attaching nut, no one will ever know if the keyway is present, or not.In Appreciation of John Hinckley -
Re: 1969 350/350 alternator Pulley
Aren't these extremely easy to duplicate on modern CNC equipment?
Right down to any tool marks?
Seems if their was a part that could be made perfectly this would be it.
However, that said, I know how much effort is put into most reproductions.
FYIO, My 63 340hp has a keyway broached into the pulley.
RickComment
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Re: 1969 350/350 alternator Pulley
The 1970831 and 3844100 pulleys are very similar, both measure 3.2" in diameter. However, the inside diameter on the from face of the 1970831 pulley measures about 1.41" while the inside diameter on the from face of the 3844100 pulley measures about 1.62". I believe that the change was made to allow for more room for a thicker socket for installing and removing the large nut. As best as I can remember the 1970831 did not have a keyway but the 3844100 does have the keyway.
DaveComment
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