I think a 5424 is 3 cylinders so that should differentiate it from the other two models. A 5416 might have Z-751 on the dipstick and a 5411 Z-500 as jrhamp saidHi-
I purchased a 1980 tall rig Catalina 30 this season which currently has a Universal diesel. My question is how do I know which engine it is, ie: 5411, 5416 or 5424?