[Woodz428]

Check the back side if the cylinder block on the drivers side. There's a raised boss that usually has the vin # stamp, they are sometimes hard to see because of the casting texture. Ford rated the engines at 335 hp (which was 10 less than the standard 428 and 25 less than the PI), estimates based on their performance were somewhere in the area of 400+. The lower rating was done to soothe the insurance demons of the day.