Most magnum pistons are .035"-.060" in the hole, which will net about 8.7-9 ratio. What I am getting at is that the cam you listed probably wants closer to 9.5. now if you are only .035" in the hole not a big deal but if you have a .060" in the hole block, you will be pretty low for that cam. What does Dave say about comp ratio with that cam? 9-9.5? The only reason I am saying this is if you have a tall deck height and factory pistons, you might want to choose a non factory piston or step down one cam size. If you want to do the math, the formula for comp distance is A-(B/2+C)-D with A being Deck height, B being stroke, C being rod length and D being deck clearance. Magnum deck height is 9.580" Stroke is 3.58" , Rod length is 6.125" deck clearance at .050" A quick calc comes to 1.615 so if I added correctly and the scummit catalog is correct for 3222HC at 1.605 that piston should put you .010" in the hole which should get you much closer to 9.5. Like I said, "if" i calculated correctly, being fairly brain dead after a long typical Monday, and assuming summit is correct, that would be the one I would choose but you might want to re run the numbers just to make sure, 3 crushed disks and 12 hours on my feet cause enough pain to make me fairly brain dead. Hope this helps. I would also call Dave and see what comp he wants with that cam along with piston recommendations. You will also need a spring kit like Dave or myself sells. Evan magnummopar.
