I have a junked 85 Monte Carlo. I noticed the upper ball joint looks the same as my 71 Chevelles. I have the factory drums on the front and would like to go with disks. Anyone tried this route?

yes, they will physically fit.
no, you don't want to do it.
beyond the puny little 10" brake rotors, you will also have major bumpsteer problems. every bump in the road will throw the car all over the place. that's not good.
if you know how to do some really basic metal fabrication, you can put anything from stock '71 11" disc brakes to 13" Corvette brakes on the stock drum spindles.