GM alternator pulley: Did I screw up buying this??

[G A.]

Did I screw up? Pictured below is what I took to be a GM 3929387 alternator pulley. It in fact measures as a 3 5/8" diameter, is a machined pulley, in this case has no p/n stamped (which is I believe not un-heard of). To me there is something missing, though I could be wrong. Not to be a smarty-pants, but does anyone here see a problem with it besides me?

[Joe L.]

Re: GM alternator pulley: Did I screw up buying this??

Did I screw up? Pictured below is what I took to be a GM 3929387 alternator pulley. It in fact measures as a 3 5/8" diameter, is a machined pulley, in this case has no p/n stamped (which is I believe not un-heard of). To me there is something missing, though I could be wrong. Not to be a smarty-pants, but does anyone here see a problem with it besides me?

Dan------


I don't see a problem with it from any kind of functional perspective. It might be that it differs from original pullies of the same part number with respect to nuances of configuration (e.g. no stamped part number, exact finish, etc.), but in all meaningful respects it should be fine.

[David L.]

Re: GM alternator pulley: Did I screw up buying this??

I agree with Joe. It's just made much later then the originals and is slightly different. There is a yellow label on the box with the date 10/30/??.

I once had an original 3829387 pulley that had the part number stamped on it as well as a key slot (which is not used).

Dave

[G A.]

Re: GM alternator pulley: Did I screw up buying this??

David - that's what I was concerned over, no slot for the key on the pulley. I could not remember if that was a requirement. Whew!! Thought I had bought me a new paperweight!!

[David L.]

Re: GM alternator pulley: Did I screw up buying this??

What is the year on the yellow label? The pulley is in the way.
10/30/??

[G A.]

Re: GM alternator pulley: Did I screw up buying this??

What is the year on the yellow label? The pulley is in the way.
10/30/??

10/30/90. Significance?

[David L.]

Re: GM alternator pulley: Did I screw up buying this??

10/30/90. Significance?

That is why your pulley does not have a slot for a key.

[Wayne M.]

Re: GM alternator pulley: Did I screw up buying this??

I agree with Joe. It's just made much later then the originals and is slightly different. There is a yellow label on the box with the date 10/30/??.

I once had an original 3829387 pulley that had the part number stamped on it as well as a key slot (which is not used).

Dave

You guys got me scratching my head . The face of Dan's pulley looks more like the one that is found in 1965 on L79, L76 and L84 (without N40 or C60, where applicable). 4 thumbnails attached; the newer-looking pulley is a '387' I bought in the GM box in the early '90s (probably Carlisle or Bloomington), for my 396 -- fits perfectly. Both are 3_5/8" dia. Offset is obviously different. Both have keyways. No stamped part # on either.

[G A.]

Re: GM alternator pulley: Did I screw up buying this??

You guys got me scratching my head . The face of Dan's pulley looks more like the one that is found in 1965 on L79, L76 and L84 (without N40 or C60, where applicable). 4 thumbnails attached; the newer-looking pulley is a '387' I bought in the GM box in the early '90s (probably Carlisle or Bloomington), for my 396 -- fits perfectly. Both are 3_5/8" dia. Offset is obviously different. Both have keyways. No stamped part # on either.

OK, so now I'm really confused. Is this pulley (the one I posted pics of) not cosmetically the same as one would expect for a '69 L-71, even though it has the same part number per GM packaging as what has been repeatedly professed to be 'correct' ? Not a big deal since the price was right, but I would like to know. I love The General but at times he reminds me of a woman, today it's to the left, tomorrow it's to the right!!

[G A.]

Re: GM alternator pulley: Did I screw up buying this??

I figure I better give you gentlemen another shot for reference.

[Grant W.]

Re: GM alternator pulley: Did I screw up buying this??

Hi Dan
This alt pulley is the type that was on my 69 L71 884 alt, 882, 825
This is the deep grooved pulley. No slot in yours is a later replacement. Nice to have a slot to keep it from spinning when you load up the 3 duces and your butt is planted in your seat.
Hope this helps.
Grant

[Joe L.]

Re: GM alternator pulley: Did I screw up buying this??

OK, so now I'm really confused. Is this pulley (the one I posted pics of) not cosmetically the same as one would expect for a '69 L-71, even though it has the same part number per GM packaging as what has been repeatedly professed to be 'correct' ? Not a big deal since the price was right, but I would like to know. I love The General but at times he reminds me of a woman, today it's to the left, tomorrow it's to the right!!

Dan-----

A GM #3829387 was never originally used for any 1969 427 except L-88 so one would not expect it to appear exactly like the pulley used for a 1969 L-71. As a matter of fact, different pullies were used for 1969 L-71 depending upon whether it was equipped with N-40, or not.

[Joe L.]

Re: GM alternator pulley: Did I screw up buying this??

Hi Dan
This alt pulley is the type that was on my 69 L71 884 alt, 882, 825
This is the deep grooved pulley. No slot in yours is a later replacement. Nice to have a slot to keep it from spinning when you load up the 3 duces and your butt is planted in your seat.
Hope this helps.
Grant

Grant------


I don't recall that any Corvette alternator rotor shaft ever had a keyway for a woodruff key, so I don't see how the keyway in the pullies could ever be used.

[G A.]

Re: GM alternator pulley: Did I screw up buying this??

Dan-----

A GM #3829387 was never originally used for any 1969 427 except L-88 so one would not expect it to appear exactly like the pulley used for a 1969 L-71. As a matter of fact, different pullies were used for 1969 L-71 depending upon whether it was equipped with N-40, or not.

Joe, I would refer you to this post.https://www.forums.ncrs.org/showthre...hlight=3829387

[Joe L.]

Re: GM alternator pulley: Did I screw up buying this??

Joe, I would refer you to this post.https://www.forums.ncrs.org/showthre...hlight=3829387

Dan------


Well, I'd say I blew it on the previous post. I just can't figure out how or why I blew it. I'm very sorry if I caused you to buy a part that's not the right one for you.

1969 Corvette with big block and without power steering originally used pulley GM #3846180. That pulley was replaced for SERVICE by the GM #3844100 which is also now discontinued..