I know this is the opposite of heavy equipment but here goes. I'm trying to determine what garden tractor this little flail mower was built for. What i have found so far is that Sunflower industries in KS made it and that company might have morphed into Sun Makr Industries that made some agricultural Flail equipment. I'm assuming it is made to be pulled from a hitch as opposed to being a belly mower. The hitch pins are 8 inches apart. The drive pully might indicate that the tractor had a right sided PTO pulley, like a Wheelhorse? It looks like it might have been painted red originally Its similar to Mott flails that were built for small tractors like cub cadets, simplicity etc. Sunflower got sued by Mott for patent infringement in the 60's.
Sunflower still makes tillage tools for ag they might be able to help. Think owned by AGCO.
I did stumble one this one mounted to a Cub. http://farmallcub.com/rudi_cub/www....-SHEAR Hammer Knife Mower-Shredder/index.html Just going by color, might that one you have there, was it mounted to a John Deere?
https://i.pinimg.com/originals/63/29/6c/63296cfe12f8955392b4a917a601e2a2.jpg cub cadet 149 has a little pto on the right. the height adjustment hardware arrangement still has me wondering if it is a belly mount, though