This is the same radius-faced bearing as supplied with many Tilton hydraulic release bearing assemblies including Part No. 163-54, 163-58, and TE 60-3330.
The 38mm (1.5") contact diameter works with Tilton 4.5" OT-V series or 5.5" OT-III series clutches (metallic or carbon) and a few AP carbon clutches (CP6913/6914 and CP7543 only).
This bearing can be used with outer race press fit pistons (as on 163-54, 163-58, and TE 60-3330) or self-centering pistons (as on the old TE 61-323). Includes nylon washer and circlip for self-centering installations. The inner race rotates with the clutch in all installations. Insert length 0.197".