The judging process for the basic engine block is progressive in nature; it starts with the block configuration and casting number - if incorrect, 350 points are deducted and engine judging stops. Next is the casting date - if correct and within 6 months of car build date, OK - if not, 175 points are deducted and engine judging stops. Next is the stamp pad - for pre-1960 cars (which don't have a VIN derivative), the pad is judged for the correct engine plant assembly date and suffix code stamp; if incorrect, 50 points are deducted. For post-1960 cars, points are evenly split between the engine plant stamp and the assembly plant-stamped VIN derivative - if either is incorrect, 25 points are deducted (or 50 points if both are incorrect). Last is the pad itself - if paint, dirt, or rust obscures the pad, or if the factory longitudinal broach marks are not present, 38 points are deducted. NCRS judging starts every car with 4500 points, and deductions are made from there, and the final raw score is divdided by 4500 to generate a percentage score. A Top Flight Award requires a minimum 94% score, or a maximum of 270 raw points deducted for the entire car (and the other areas judged, other than the basic engine block, are assigned 3887 points), so it's not possible to get Top Flight with the wrong casting number engine block.