the same numbers should also be cast inside the block near the crank bearing (not the pan the block) and also in the heads beside the rocker arm assembly but some engines (pretty rare) dont have the numbers cast in the heads though i dont know why, easiest way to identify a 14-20 hp vanguard that doesnt have any id tag is to pop a valve cover and check the casting number 30-35, the 38 vanguard heads are cast differntly on the outside near the exhaust flange so those are easy to identify hope this helps