Valve springs can break on these even with low miles, might as well put in new ones while you got the motor out, since your doing that you might as well get 6.4 springs and the matching cam (cam is way bigger and only cost me $68 at the local dealer). You can reuse the stock pushrods but check for wear on the rocker end, we have had a lot of luck fixin the infamous hemi tick by putting in new pushrods, you could also look into getting a custom PR .050 longer than stock but it don't seem to be needed.

They came with 395 ish HP, that cam should put you way over the top. Heck even a good set of long tube headers should do the trick but they cost a lot more unless you are planning to use some anyhow.