Video claims the later piston isn't thicker but it is; the early 2124834 piston does measure .780" thick but the '74-later 3743623 piston measures .830". The thicker piston is needed because of the reduced cone height of the new Belleville. The later piston and Belleville were introduced to prevent the exact same failure mentioned in the video.

Use of the late piston and Bellevile along with replacing the wavy snap ring with the thickest solid snap ring (.106") makes the rear clutch a lot more reliable without the big bucks for the billet parts.