Some 5.9 roller cam help from y'all please

I'm confused as to where this EQ heads only support 470 lift out of the box? That info seems to be false. I bought a set of bare heads through Magnum Mopar, with the cam he recommended. My stock heads were cracked. Took it all to the machinist, where he double checked the valve grind, and then reassembled with most of the original parts, less the springs keepers, retainers and seals. Everything was good to go, and the springs and heads had plenty of room to spare. Just wrapping up the engine this week.