Eddy heads max lift?

It's less a function of the heads and more of the shop doing the head work. I've seen them go .700 with Eddy supplied valves but I think that was with +.100 retainers. You have to start looking into longer valves and taller installed heights beyond that. It also takes modification of the rocker shaft supports IIRC. Honestly if you feel you have to go through all that work the RPMs are not the head you want. Go buy the Indy 360-1s.