bought a new rear end and have some questions

[Squareforceone]

So I bought a 12 bolt rear end out of a 80 k10 for my 84 c10. New rear end is a 12 bolt posi 3.73 6 lug. Old rear end was an open rear end 10 bolt 5 lug. I want to run the 12 bolt with 5 lug axles I know I will need shafts from a factory 5 lug 12 bolt. I think my brakes will all swap over. So my question is what else do I need to change to make this work I heard there was a different u-joint? Anything else? Also this is a budget built do you think a junk yard would sell me just axle shafts? If so what trucks should i look for with 5 lug 12 bolts if any? Thanks