GM factory large Alternator pulley

[Bernhard]

Hi
How can you tell if you have a factory original GM large diameter Alternator pulley or a reproduction?
What should I expect to pay for a original OEM one?
Thanks
Bernhard

[rszmjt]

Original production line installed deep groove alt pulleys on 69 Z28 has 3 small slashes that start at the inner counterbored hole where the nut is and go towards the outside belt groove, they are not very prominent and are hard to see sometimes. Hope that helps. Cheers.

[Bernhard]

Thanks for the reply.
I found this reproduction deep grove alternator pulley is it a good copy or average?
https://www.speedwaymotors.com/Class...vy,116351.html
If I can't source an original maybe this is a good back up?

I'm starting from zero as I have no knowledge about these pulleys other than seeing them on cars at the track and shows.

I have come across two factory numbers/codes for this style of pulley W-645 , KW-608 anyone no what the difference is ?

Thanks
Bernhard

[rszmjt]

Decent copy, but it fits 67 Z or non PS Corvette. What year are u working on?

[William]

There were two versions:

67 used a 3.6" diameter pulley with a hard-stamp part number 3829387 AI
68-up used a 3.2" diameter pulley, no part number.

Both were silver-cad plated. GMPD serviced 3829387 but it was incorrectly plated.

FWIW one of our customers was a rebuilder of starters and alternators. One of those pulleys was also used in aircraft applications.

[BCreekDave]

Originally Posted by William

There were two versions:

67 used a 3.6" diameter pulley with a hard-stamp part number 3829387 AI
68-up used a 3.2" diameter pulley, no part number.

Both were silver-cad plated. GMPD serviced 3829387 but it was incorrectly plated.

FWIW one of our customers was a rebuilder of starters and alternators. One of those pulleys was also used in aircraft applications.

How do we account for this:

http://chevynova.org/1970LT1_Engine.html

wrong alternator?

[rszmjt]

Originally Posted by BCreekDave

How do we account for this:

http://chevynova.org/1970LT1_Engine.html

wrong alternator?

Yes it was missing when I got the motor, that was a corvette alt and pulley i had laying around

[Bernhard]

Originally Posted by rszmjt

Decent copy, but it fits 67 Z or non PS Corvette. What year are u working on?

Bernhard wrote:
Thanks for the reply
I was thinking about running one on my 69 442 post stick Jr stock tribute.
I don't know if they were legal or not in jr stock, but I always liked the look of the factory large diameter pulley