Max valve lift of econo W2

340x head..with the right spring/retainer/lock combo plus any cutting into spring pocket...probably .650 gross...

long valve w2 head....with same as above...probably over .750 gross

econo head....long valve or standard valve....long will be the same as the w2 above..and standard valve would be the same as a X head since they would use the same length valves..