Wanting new control arms- discs on my 68, a few questions!!

[sy2767]

I'm a totally new to this so please educate me. I am wanting to swap the original control arms and drums on my 68 to some newer style control arms and discs. Can this be done without changing the crossmember? What needs to be done to put new control arms in? Does a vendor or company sell all required parts? ( i know i will not find anything locally and i don't want to put 30 plus year old parts on my truck.