Just finishing up the install of a fresh 500hp 408" Magnum with a track loc'd 3.91 geared rear end, and a 200R4 transmission with a 3000 rpm stall/ Lock-up clutched Precision of New Hampshire torque converter using a bolt on bellhousing with adapter. I have to bolt the front end back together today and do some test driving.
It did require some cross-member massaging on the driver's side with subsequent additional reinforcement and a custom made cross-member, but the floor didn't need any massaging. It left me with a -2 degree nose down pinion angle. Everything is tucked up nice and neat.