small mods for a 71 monte carlo

i was hoping someone out there could help me with a couple of question :

1- i am seriuosly thinking of converting the rear drum brake system to disk brakes, if this possiable, how or where could i go to get that information ?

2- this car is my sons and i am also looking to replace the current seat belt system with a more modern restraint type system, in stead of the old lap belt and roof contectd shoulder harness ?

this wont be the last questions i have but it is a start

why would you want to put disc brakes on in the first place????
and ive never seen it done.....dont think i have??????
buy him a racein harness if your that worried about seat belts