73 up "spool mount" small block to big block conversion mounts $65

Kim: They DO look narrow. I haven't seen any like them before. There ARE outside chunks of the rubber breaking off but it doesn't look rotted.
I didn't get any type of paperwork with them and I don't have a block or a k frame to try them on. IF there is a left and right, it would be determined by the off spacing of the bottom of the mount. They do look slightly different to me. I have all the reservations that you have so I don't want anybody buying them based on what I know, because I don't know much :)
Sorry to be so little help.