3844100AK Pulley photos and dimensions needed of an assembly line pulley
 

Looking for photos and dimensions of an assembly line 3844100AK alternator pulley. Bonus if you have one to spare.

Here ya go ;)

The NOS in box ones don’t usually have numbers stamped

What applications was this pulley installed?

The dimensions listed in the 7/1/1967 parts book were:

Outside diameter: 3-7/32"
Shaft [hole] diameter: 43/64"
Groove width: 1/2"

I can only speak to 65-67 Chevelle usage, but this was the factory pulley on 65 Z16's and 66-67 L78's. It also came on the 62 amp "AC generator" option in 65 and for at least part of 66.

Some assembly line pullies were stamped, some weren't. I do not know if that was a matter of two different suppliers (each supplying different assembly plants), or a timing matter. I can only say for sure that

- the pulleys on Z16's (all built at KC) were not stamped,

- I have seen some original 66 Chevelle L78 pulleys that were stamped and some that were not, and

- so far I have never seen an original 67 Chevelle L78 pulley that was stamped.

65-67 Originals were all cad plated. Later NOS replacements are cad-dichromate or zinc-dichromate (the goldish colored plating).

Thank you for the wealth of information. I ask because I have a 1967 Camaro L78 04D car and want to recognize the correct part when I see it. I would hope both stamped and unstamped pulleys would be correct with original cad plating for my Norwood built car.

This reminds me of how lug nuts were made by different manufactures... some with waffle pattern, some without, yet the waffle pattern seems to be the most "correct" and desirable now? Is this the case with a stamped 100AK pulley?

It's also called out in the full size assembly manuals for '65 L78 and '66 L72.

If there were two suppliers (one stamping and one not), then I think you would need to get advice from someone who owns or has pics of an unrestored Norwood L78 to be sure.

If it was a timing thing, then I would say unstamped is more likely correct. As I said above, I have never seen a verified original 67 Chevelle L78 pulley that was stamped. Here's my Baltimore July built original, as found before the car was awakened from a 37 year garage slumber.

I have received photos of my original L78 04D engine as pulled in the late 60's early 70's by the original owner. The last photos are closeups of the alt and pulley now as provided by the current owners of the engine. The pulley is definitely a 3844100.

However it does NOT have a stamp but as previously discussed on CRG, later NOR cars appear to have a stamp.

I include this data to prove early NOR L78 cars also used the 3844100 as illustrated in the AIM. Perhaps leftover pulleys were used from Chevelle production for early cars?

Jose

Nice, great research and follow up!

Are you sure it's not a #1970831 Alternator pulley?

Yes according to the measurements. I'll ask owner to double check diameter and confirm keyway slot.

Someone please correct me if I am wrong but there have been at least a few 67 cars witnessed with and without the part number stamped and as being originals.

I can tell you that every survivor 67 L78 camaro in the reg. that we have seen always has the stamped pulley from an early 4p L78 survivor to a july survivor. But i would never say they didn't come unstamped. Stamped pulleys are tuff to find. La cars may have had a double alt pulley. I've found 2 100ak in 20 years

Luckily I've sourced a stamped pulley (Top pulley). If I can get the current owner of the engine to measure the pulley and check the keyway I can confirm 100% it is a 3844100 (spoiler alert I won't). Bruce (the original owner) did race the car and its not impossible the alt/pulley were changed. I'll be running my stamped pulley on my car for now. It feels like the more I learn the less I know.