As Monte pointed out Bore has a much bigger affect than stroke on how much power is made. With Mopar heads just not sure the added stroke is worth the hassles. Look at the GM stuff, compare a 540 to a 555 to a 565. The difference is bore diameter. Stroke is the same on each of these engines and no question a 565 makes more power. All the GM motors make more power because they have a larger bore to work with. 4.600 is a big deal over a 4.500 bore for sure.