have you ever seen this kind of drum

My '71 EL5 GT had them on the original SBP 8 3/4. I've seen them called "bell" drums before. I've heard they were more common on export cars, but that's just something I heard, I don't have any evidence. My EL5 Gt that had them was a Windsor car built for US export. My LA built GK6 Gt came to me without it's original 8 3/4, so I have no idea if it had them too or not.