New to group. Up date suspinison 65 suburban

[65burb65]

I just bought a 65 suburban short wheelbase 10 series with six lug wheels. I have a salvage yard and woundering what I need to up date to 5 lug disc. I heard I can leave my crossmember in and bolt every thing off a 84 chevy to it. Also I have tried to email captian fab with no response about a adapter plate for the power gear box. What about changing rear axle to 5 lug. My suburban used to be a school bus in southern mo. When it was new, still has the lights on the roof. Plan on lowering it and 350 400 turbo trans. Anything I need to look out for? Thanks for any feedback