1970 duster small bolt to big bolt spindle swap

Yes that is the only reason i am wanting to switch is so i actually have a bigger selection of rims, i have cragers and slots, but would like to go with center lines or weld wheels. I just replaced the master cylinder and am pretty happy with my brakes now so i didn't really want to have to shell out a wack of cash to go to wilwood or something like that. I also only drive the duster a little during the summer too so there isn't very many miles put on mine either.
I am a little supprised by the stud still being in there and the new stud sitting flush, but i figure they do it, and they know what their doing so it has to be allright.
I do appreciate everyones oppinion for or against this. I have also heard about the safety side too, but haven't ever actually heard from anyone who actually had problems with safety going this way.
Thanks