just bought my 81 silverado and its nice and runs great but i would like some help with where i should start.

specs: 350 w/headers glasspacks , all rebuilt 4in lift on 33'

i just want to start with getting the suspension and all the above ready to take some damage before i drop my big block in it. what trans case and rear end should i put in any help will be great  

first off start with a 14 bolt 10.5 full floater rear axle, a dana 60 front would be nice but a dana 44 is pretty stout depending on how big your tires will be, the strongest case you can put in would be a 205 but i kinda don't like its not so low "low range" the 203 is pretty strong but its full time, ive got a 208 in my blazr which has held up so far but i don't know how it would do behind a big block  

If you want the 'strongest' put a 14b in the rear and a 205 transfer. That's what I would do anyway.