'65 Barracuda drivetrain swap

I am kinda curious about how you got the early torque convertor required for the 1965 trans mounted to the later crankshaft. The 273 crank hub/convertor pilot was smaller than later engines which means without a special spacer ring your torque convertor doesn't locate properly on the crankshaft. That could be why your front trans seal is leaking the convertor may have some run out.

I recall member "CharlieS" as being a good source of the convertor spacers.

I would retain my original trans just to not have to bother with kickdown linkages, speedo cables, shift linkages, driveshafts.