454 nice choice of an engine to set inside those wheel wells...
Ok, if you are familiar with removing and installing a sbc, then there's no difference between the sbc and bbc. The motions are the same but, there's some extra metal on that bbc that you need to be careful of.
1. You might want to remove your hood to get the proper angle of getting the old motor out and the bbc in without damaging any sheet metal.
2. Photograph everything before turning any wrenches. This way, you have an idea where everything goes when you put this bbc back in.
3. Engine mounts. You will need to move your motor mounts to the correct location within the compartment. I can't remember if you have to go fwd or backwards in order to do so... Never had a bbc so hopefully someone will chime in on this..
4. Transmission. Hopefully you have a stout transmission that will handle the torque of that bbc.
5. Radiator. Time for an upgrade to accommodate the cooling requirements needed to keep it cool.
6. Exhaust. 2.5 to 3"
7. Take your time. Have a friend or 3 stop by and assist you. Trust me, doing this is not a 1 man job.
8. Engine lift. Make sure you have an overhead hoist or cherry picker set-up correctly to ensure the motor is lifted correctly and safely.