1966 Chateau Slate L78 Chevelle

[OneStopRestoration]

Novadude, My dad is restoring a low miles 67 Chevelle SS that came with an M21. In taking that trans apart we found the same torque locking slider for the 3/4 gear set. We know that cars history back through 2 previous owners, neither of which touched the transmission since new. It had been a mystery to me why GM pulled a speacial part number M20 separate from the 325 or 360hp cars. It became clear in finding the same torque locking slider in my 66 L78 M20. I cant speak to the M22s of the era. Its funny so many people probably never have checked or just toss the originals in the trash during a rebuild. Like i stated this is my theory but I believe its good evidence to represent an additional distinguishing difference.