I will add in the event it may not have been covered, ONE reason DVW swapped to the ISKY lifter is his older "COMP" lifters were forking at the wheel. From my recall, he had about the same spring load but a different spring which was a tick over 300 seat and over 800 open for posterity. The forking occurred some time after a short number of runs too 150ish IIRC. His was not the first set of Comps I've seen do this at these loads.