I've got a few misc pulleys I've collected over the years. I think I have a matching wp/crank set but not sure. The rest are non musclecar years I think. Can you tell what their original application is by the #s stamped on them?
Some will have the last 2 numbers of the part number that is normally on the build sheet.
The last two #s are a much larger stamping on each piece. If that corresponds to the build sheet #s, then it makes sense that they would be larger...so the line workers could easily see the correct part. I don't think these are anything special.
water pump 2951836 single...looks very close to the one on my Challenger
water pump 3751126 single...small diameter
water pump 3698805 two groove...small diameter
crank 3614378 two groove...looks just like the one on my Challenger
crank 3614377 three groove