It's more about the solid rubber composite of the rag joint. Anything else would be inferior IMO.
The diameter of the OEM is 3" and the thickness is approximately 1"
A seller on eBay has 7 left @ $200 each - supply and demand. Pricey, but he appears to be the only source for these.
1973 Satellite Road Runner Charger Coronet NOS MoPar RAG JOINT COUPLER Chryco
NOS MoPar #3575303 sheering shaft insulator for just above the steering box on 1973 Satellite, Charger, Road Runner, Coronet, B Body cars and all 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973 full size Plymouth, Dodge, Chrysler, and Imperial models. This may be offered in aftermarket catalogs, but ONLY the part Mopar sold actually works. Fury, Sport Fury, I, II, III, GT, S-23, Polara, Monaco, 500, Newport, New Yorker, 300.
MADE IN USA!