Originally Posted by hughj
Hi engine guru's. My ZZ502 crate engine came with stamped steel rockers (1.7 ratio). Is there enough piston / valve clearance to go to a 1.8 ratio roller rocker? Would I have to change pushrods? Would I gain enough performance to make it worthwhile or stick with the 1.7?
There is enough difference in tolerance stack ups from engine to engine that this is best measured for the specific engine. Generally there isn't a problem, but given the cost of fixing a parts collision I wouldn't hang my hat on that. One of those things where the probability is low but the consequence high on a risk chart.