There's really nothing that needs to be done to the block to go to a roller. You will need a cam thrust button to insure that the cam stays to the back and doesn't shift forward. You'll of course need linked roller lifters ($$$), shorter pushrods, and a bronze distributor gear. Plus make sure you check the valve to piston clearance. Roller cams have more aggressive ramp speeds than flat tappet cams so the chance of interference is greater. Otherwise no big deal.
BSE Racing Engines