The cushion is most likely the same. The cushion to block brackets could be slightly different. Most likely easy to make fit. Oil pans as well as converter or flywheel are different as well.
F bodies use spool mounts, not biscuit mounts. As Poorboy said, the 318 mount will fit on the 360 with a spacer. Poorboy's advice on the balance issue is also correct.
All the 318 accessories should bolts right up. Exhaust manifolds should, but test fit them on the engine stand first.
You can see the space in the following picture from my 318 to 360 swap in my diplomat.
