BB Mopar to 8HP has been done. This the only one I know of though...
Lots of custom one off engineering, machining and fabrication in this build. My 8HP70 swap.
Not aware of any retail swap "Kit" for 8HP to BB Mopar yet.
I would probably look into getting an 8HP90 (900 Nm) though for Big Block torque handling, vs 8HP70 (700 Nm) if you were not already thing that...
663.8 lb.-ft. HP90 vs 516 lb.-ft. HP70