Gm 3921923bm single groove pulley ?????
 

I have looked this part number and every thing I see is a double groove...... not single ???? Any help on this ????? thanks joe

I've seen the second groove machine/cut off plenty of pulleys.

This is not cut at all

Post a pic of it, if you have it. I have had one of these for years, same p/n and wondered if it was orig or not. I cannot see Chevy having the same for a single and double groove pulley, but who knows for sure

Gm 3921923
 

Here are some pics As you see it has not been machined thanks joe

...5291 is the BB double/deep groove pulley p/n

The early cars had driver pulleys for the power steering cars. Ive never seen a single groove 923 . No way the single groove is a replacement it would have to be the other way around