66 Cuda 360 questions
Yes you can use the 273 Motor mounts but they need to be modified to fit either 340 or 360 applications. They will require a triangular piece to be welded to one of the mounts but you can buy aftermarket motor mounts too.
Transmission crossover is the same for manual or automatic car but transmission mount is different. Its also a good time to cut away material on the crossover to accommodate dual exhaust (helps to eliminate potential exhaust pipe rattling against crossover).
The Z-Bar will be a challenge, you will need to acquire the body side pivot bracket (hopefully your car is pre drilled for one), also you need a pivot bracket for the motor side (I made mine by modifying one from the junkyard but I have heard they can be purchased. I do not believe the 273 bellhousing pivot bracket will work because the 10.5 bellhousing is different from 273 (9.5 inch) bellhousing so buying one from eBay not useful. I also made my z-bar from a longer truck z-bar (like yours) by cutting away excess between the forks (in the center of the z-bar) to fit between the pivots and re-welding it together.
Shifter will require a hump be welded to the existing tunnel.
Bills right
Your going to love the ride
Good Luck