Gen 3 426 into aussie a body

Hi all, I am looking at the potential of installing an all allow 426 Gen 3 into my Aussie A body Charger. I have some concerns though and would appreciate any persons valued advice, Is there enough room without fouling anything major, i.e. the heads are they larger will they foul the brake booster. What mods will I have to do to my existing K-frame which is a 6 cylinder type?, can I run rack and pinion steering ?, because I would like to?
At this stage I am a bit green to the Gen 3 motors.
I am a fitter by trade and have worked as a welder in the past so I can fabricate and modify but would prefer within reason a straight forward installation (Yes I appreciate there probably is no such thing).
Look forward to your feedback.
Regards Scotty (Barneynitrous)