Where is the block casting number located on a ford 400 engine? John?

Where is the block casting number located on a ford 400 engine?

Its located on the side of the block, passenger side, below the cylinder head near the last spark plug hole, right above where the starter mounts. The 351C and 400M both have the same casting number. The only way to tell them apart is to remove the oil pan and check the casting number on the crank. The 400 has a 4.00" bore and a 4.00" stroke