You need to make sure the geometry is correct, the pushrod length will be critical, and the lifer preload needs to be right. You can use factory stuff, I have to over .530 lift with no stability issues over 6K. But with more modern grinds and ramps, and the springs they require, you will find the shafts begin to deform and the rockers flex. the bigger the engien, the bigger the cam needed. If it were me, I would use the sintered iron rocker setups from Crane or Isky long before stamped steel. They are about $100 less than aluminum rollers, and more stable. Plus, the ability to set lash and use teh adjuster screws means an easier time makign up for tolerance differences that lead one to run say, 3 different pushrod lengths in the same engine to get the right preload..lol.