Trying to figure out what this is it came out of my 64 barracuda 318 4 speed

The original clutch disc at least for the Commando 273 was 9.5 inches, not 9 1/8. The replacement clutches for them got to be hard to get even by the early seventies; buy one from the local parts store and you got a six cylinder clutch. i went through a couple of them, got tired of the clutch slipping when speed shifting, finally discovered that Weber made a high performance clutch in the correct size, but you had to have a strong knee to hold the clutch in at a light. Plus it would bend the release levers after a couple of years, so after two of them I switched to a 340 10.5 inch clutch. (Brewer offers a clutch torque shaft for a 10.5 inch bellhousing in a 64-66 A body. Brewer's Performance - Mopar A833 4-Speed Transmission and Component Specialists)

Have no idea how well the Brewer small clutches work, but I would sure try one if I still had the small clutch/flywheel. Brewer's Performance - Mopar A833 4-Speed Transmission and Component Specialists