Replacing original trans.

To clarify zijimer, only 64-67 torque converters will work with your engine. Later ones had a larger diameter snout that won't fit in your crankshaft's hole, unless you machine the crank. As he said, you can change internal tranny parts to use a 67- converter in a 68+ transmission. 66+ transmissions are lever shift.

I think there is a way to adapt your cable shift to an after-market shifter, but not positive. I think 65 transmissions used the now-standard P-R-N-D-2-1 pattern, unlike 64-. I think their valve body is 1-year only. At least true for my 65 C-body.