I've got an '80 with 440- used the shoemauker(SP) mounts and used c body exaust manifolds that are simalar to the RR ones.
Also had to slightly lower the pass inner fender just above the A-arm cam bolts for exaust manifold.
The only other thing that I can remember is I clearanced the K frame where the filter is (could have gotten by but gave it about 3/8 clearance.
Put a 68 imperial motor in w/50k on it runs REAL good --wife likes it
Kept all A/C hooked up and works great!
We really like the car,still got some more tweeking to do but too busy bailin hay!