Dwayne, have you taken a look at how much valve lift a guy can run with these heads? It looks to me that .750 is easy right out the box with a spring change. Not sure if they'll go 0.800 lift or not but it looks really close. I think a set of Manley 221420 springs will fit in there and they should go 0.800 lift at 2.00 installed height.
Andy, the roller springs that come on those heads would likely be suitable for just about any roller cam I would use with them. If I were putting something together that I thought needed an .800 lift cam, I would just use bigger heads.
That Manley spring is like 900lbs open. I can't see myself opting to run that much spring with a normal shaft set up that only has five 3/8" studs holding it in place, and that much span between the studs.
I have no doubt that it won't be long and someone will put a set of these heads on something and run .800 or more lift, and make good power in the process. I just don't feel like that was the type of build these heads were targeting. I'm sure 700hp+will be easy enough to make with a pretty simple 505rb combo and a cam that would work okay with the supplied roller springs........ And that's more along the lines of what I feel is the main type of build these heads were intended for.
