No, not the casting number but thanks for the info. The one I'm looking for is the vehicle identification number. I'm about to buy a 2000 GT and the seller said the car has a 2004 GT motor in it. He doesn't has the receipt for the motor and therefore I don't know if it's true or not. The only way to find out is to look for the VIN that stamped on the block. I know the old 5.0 motor has the last 8 digits of the VIN stamped on flat surface on the back of the motor right below the lower intake area. Not sure about the 4.6L block.