I would watch the ENGINE MASTERS episode where they dyno the early version of the 5.7 against a newer (09 and up) what they call the "Eagle" version 5.7. If I were to spend the money doing a 5.7 swap I'd look for a later version which will gain you over 100 horsepower difference. The later versions have a much better head design flowing around 330 cfm.
I have driven an '06 Charger with the 5.7 and own a 13 Ram with the newer 5.7 I can tell you at WOT the truck pulls way harder than the Charger.