Torque Converter Design Change

Can someone define the difference between the T.C.'s installed beginning in 1977, compared to the 1976 and before?

My concern is the thickness of the 4 Mounting Pads. 1976 has THICK pads and 1977 has THIN pads. I understand all the 'Balance Weight' issues, that part is simple. My question is the Interchangeability of the 76 back with the 77 up non lockup converters.

To clarify, I'm not referring to 'Lock Up' 23 spline versus 'Non Lock' 24 spline.

Thanks for help!
Bruce
Author: MoparapoM