suspension upgrade revisited

[gunnersm8]

heres my thoughts/theories. need a "quasi" expert to help me out

73-87 front ends, im going to beat this horse to death as ive looked everywhere and yet to find the answer. heres the question...i get the whole pile of crap from the junk yard, spindle to spindle, replace spindles with drop, replace brake items with that year at parts store, replace bushings/ball joints with PST poly kit, why am i taking everything from the junkyard? is there other items that im not thinking about here?

next question-rear end/5 lug conversion. ive read over and over that the 70 and up axles are longer than 60-70. so if i find the same 85chevy, and take those axles, cant i just take them and have them cut and resplined to the length i need? ive been told thats fairly cheap(50$) and any machine shop can do that. i dont want to unbolt the whole rear end for change out, or move spring perches,etc, plus i like my 4.10 gears....hehehehe