Much more important on a Mopar than stroke are cylinder heads. If you are not going to step up and get some good heads then dont bother. I would spend my $$$ on EQ heads w/upgraded springs and a larger roller cam. 5.9L Magnum with EQ heads will easily make 400 +HP. There is a link to an article on our site about 1998 5.9 w/160K pulled form wrecking yard, swapped out EQ heads, MP 380HP cam and air gap/holley that made over 400 hp w stock 160K miles short block.
As BrianT stated, getting the rest of the package is super important, a local guy in Oregon has won lots of National Class Champs running 5.2 Magnum short block with EQ heads and Racer Brown cam against 440's and 426's consistently. Heads are a big part but so is weight, traction, gearing etc.
BTW, Jim's 67 Barracuda hangs huge wheelies with 5.2L