You can probably stoke it easily, but not with the stock pistons....the pin height is different because of the longer rods. And yes, use the longer rods if you're going to stroke it. Pat will offer more on this. Im not terribly familiar with the 502 blocks, I have done many 454's of the older variety. I dont know if those earlier heads you mentioned would be too large of an intake runner on that engine....yes, they're big, but I run 327cc intake runners on rect. port heads on my 505 stroker, and I can tell you it's anything buy soggy at low rpms!! or any rpms for that matter. John