RAU sells 3 part numbers for a 225: PL33, PL33S and PL33H(Hydraulic). The PL33 is the same across the mechanical lifter line. The S is for 75-80 225's (cast crank and its bearings, what else changed?) but I don't know what the diff would be rocker arm wise. @slantsixdan
It's possible the arms are the same (they should be) but the difference being the rear mounting hole in the shaft. That hole did change somewhere around that time frame (not sure of the exact year).
