Just curious,

How does one know for sure which trow-out bearing is needed? Does it depend on how long the disk horn is toward the P-plate? Example of two styles?

https://www.classicparts.com/1938-75-Clutch-Release-Bearing-1-7_8/productinfo/90-205/

https://www.classicparts.com/1951-84-Clutch-Release-Bearing-1-1_4/productinfo/90-211/