I've done alot of research on this, as we are using a ZZ502 as well. So far I still have not decided exactly what we are doing, but 1K sounds like a bit much for a very small change in lift and duration. If you havn't puchased yet, get the 502 Shortblock add a set of AFR 315's and a hydraulic roller to match. Should be good for 625+ with the correct induction. JMO Check out
www.lewisracingengines.com Give them a ring and talk to Mike. Great guy to talk to.