A500 and A518 Parasitic loss

May fit the tunnel itself but ya still have to hack the torsion bar crossmember. I know someone sells a piece that goes in there but you still have to cut it up.

Yes, very nice kit manufactured and sold by US Car Tool. The kit is designed specifically to install the 200-4R in a Mopar A-Body. Take a look at the pics on the link:

67-75 A-Body GM2004R Cross-Member Kit