Still adjust the pushrod the same way. The 18 flats will adjust the cushion in the lifter to about .100". This is the correct adjustment. You can tell if the lifter is bled down by turning the pushrod with your fingers. If after the adjustment you can't turn the pushrod with your fingers it is because the lifter is pumped up still and holding the valve open and when you try to turn the pushrod, the valve spring is exerting too much force and you can't turn it by hand. After the lifter bleeds down, the spring pressure is released from the pushrod and thus it turns freely by hand (fingers).