My chosen engine shop that does my machine work wasn't afraid to tell me to go a full 4.500 bore right from the start. His opinion is take care of the motor well, and when it loosens up after a few rebuilds, hone it out to 4.502 or what ever the smallest it will clean up and order new pistons. You can do it again down the road if you still have the same motor. With rings being available in .005 over, as long as piston makers will custom make a slightly bigger piston, you can get a lot of life out of a Mopar 4.8 bs block.