1970 Duster - 383

So guys I have a couple of quick questions before I dive into this weekend. I would like to get the suspension work out of the way. Last week I took out the leaf springs, shocks, and 7 3/4 rear end. I have a 8 3/4 with 2.73 running gears and the small bolt pattern.

My questions are:
1) I have a 73 parts car with better looking springs, can I use those on the duster or would you recommend buying new springs?

2) My car was not a sway bar car. The slant six K member does not have the bracket/holes to mount a sway bar. The 73 duster that I am using for parts has a sway bar. Can I drill holes into K member on my car and mount sway bar? Or would you recommend buying sway bar that mounts to the shock like some of the aftermarket kits?

3) Finally would you guys recommend getting new axels and the rear end re-geared before I put it in?

I’m sorry for the questions, just need some advice. Thank you.