Pulley

[Carmelo P.]

67/ l79
Pulley #3920387 AI,
originally have a keyway?
How can I determine if this one's a re-pop or gm replacement?
Thank you

[David L.]

Re: Pulley

Attached is a photo of an original 3829387-AI pulley. It was on my 1966 Corvette with non-original engine when I bought the car in 1979.
Dave

[Carmelo P.]

Re: Pulley

I see yours has the keyway, meaning the alternator shaft would have a woodruff key ?

[Joe L.]

Re: Pulley

I see yours has the keyway, meaning the alternator shaft would have a woodruff key ?

Carmelo------


Many GM alternator pulleys have keyways. However, no 1963+ Corvette alternator has a keyed shaft so the keyways are not needed for the Corvette applications.

[Carmelo P.]

Re: Pulley

ok, knowing both would work, would the pulley without keyway be an original pulley for a L79 in 67 ?
Thanks for the replies...

[Joe L.]

Re: Pulley

ok, knowing both would work, would the pulley without keyway be an original pulley for a L79 in 67 ?
Thanks for the replies...

Carmelo------


As far as I know, the original GM#3829387 pulley always had the keyway but it is possible it was added to or removed from the spec before or after 1967. Most of the reproductions do not have the keyway although I've seen some that do. In any event, the presence or absence of the keyway is a moot point as far as judging is concerned as there is no way it can be discerned with the pulley installed on the alternator. As I've previously stated, the keyway is, functionally, irrelevant for a Corvette and, for that matter, all other Chevrolet passenger car applications that I'm aware of.

What's important is the visually discernible configuration of the pulley and the part number. From what I can see of yours, it appears fine to me. Of course, there may be some visible nuance that judges look for that is lacking. Others will have to comment on that.

[Carmelo P.]

Re: Pulley

Thanks Joe.....

[David L.]

Re: Pulley

I see yours has the keyway, meaning the alternator shaft would have a woodruff key ?

No keyway on my 1100693 alternator dated 6 B 17 (feb. 17, 1966). The body build date on my 1966 is "F24" (Feb. 24, 1966). I have always assumed that the alternator was original.
Dave

[Joe L.]

Re: Pulley

No keyway on my 1100693 alternator dated 6 B 17 (feb. 17, 1966). The body build date on my 1966 is "F24" (Feb. 24, 1966). I have always assumed that the alternator was original.
Dave

Dave-----

Yes, no Corvette (or, other Chevrolet passenger car) alternator that I am aware of ever used a keyed alternator shaft. Since the pulleys had very wide applications beyond Chevrolet passenger cars, some of the pulleys had the keyway slot. The slot accommodated the applications requiring it but did no harm for applications not requiring it.