I had heard Terry that GM ceased using the Muncie (in M22 form anyway) as hipo big blocks and engines like the 1970 LT1 dissapeared in production cars. They went back to the T10 as it was strong enough for what thy had, but never rated high enough for big engines.

I thought GM developed the T10 with Borg Warner for the 1957 Corvette, and then BW used it elsewhere once GM started their own production of boxes. I knew BW was involved from the start, but GM were heavily involved?