Most engines never have all the push rods spinning at equal rotations..it may be due to a cupped lifter base or worn cam lobe ,but I've seen plenty of engines with no issues with lifters or cam lobes not spin every push rod at the same "speed"..
The base of a lifter is supposed to be convex slightly,so as it rides on the cam lobe,it'll spin,rather than scuff away on the same spot..if a lifter bore gets gummed up with sludge or old oil it can prevent it from spinning and cause rapid cam lobe wear..once the lifter bottom gets concaved some it'll stop spinning ..but I've had engines with several cupped lifters and not much lobe wear that ran great ,until one lobe wore down enough to start it "gargling" back thru the intake at higher rpms..
The base of a lifter is supposed to be convex slightly,so as it rides on the cam lobe,it'll spin,rather than scuff away on the same spot..if a lifter bore gets gummed up with sludge or old oil it can prevent it from spinning and cause rapid cam lobe wear..once the lifter bottom gets concaved some it'll stop spinning ..but I've had engines with several cupped lifters and not much lobe wear that ran great ,until one lobe wore down enough to start it "gargling" back thru the intake at higher rpms..
