I take it you're new to Mustangs or Fords for that matter. 351W engines have the dipstick in the front also. All engines in these cars have a front sump oil pan unless it has been modified. And what D.Hearne said. 351C has a 4 or 2 cast on the top corner of the head that indicates whether it's a 4V or 2V head. It's visible without removing the rocker cover. You do need the numbers to determine if a 4V is a closed chamber or open and what year of head.