My pleasure Tom, happy to clarify these VINs. As for 332575, I've heard the same stories as you, and I know some people who have seen that car firsthand (unfortunately I haven't). Details beyond that are not real clear.
As for the shaker on 221640 that has been added, and it was also added on my car long before I got it. To my knowledge aside from perhaps the Diamonte (before it became a concept car) all the known Hemi Challenger converts came with sport hoods, but no shakers.
Value, rarity, and cool-factor-wise I agree with most of the comments above, the problem is that there are so few Ebody Hemi 'verts, no two cars are configured closely enough to be evenly compared, and they trade hands so rarely, that it is hard to see patterns. If you asked me, comparing prices I guess on average they would stack up roughly as follows:
The average '70 Hemicuda convert = ~1.5x more $ than the average Hemi Chal convert
The average '71 Hemicuda convert = ~1.5x more $ than the average '70 Hemicuda convert
- Wade