Can have 3, 4 , or 5 clutch plates, and the same number of steels.
Normally 3 clutch plates.
4 plates for HD high horse power applications.
5 plates only in some 440 6 pack, and 426 Hemi applications. The drum is also wider.
1962 to 1970 drum has the narrow bearing bush that rides on the rear of the pump assembly The clutch supply is by 2 holes..
From 1971 onwards the bearing is wider and the clutch supply is via a slot. The seal design for the clutch apply piston also changes.
The clutch apply piston has few changes, except for the changes for the different seal design change in 1971. The return spring positions can come with 10 positions, or 15 positions. However not all the positions are used. The number of return springs used can be from 6 to 12 depending on the application.