The Engine Serial Number that was stamped into the block in the ledge in the block (to the rear of) the distributor can be ground-away and changed to a new number. This was commonly illegally done in order to get a used vehicle registered.

Look at this page for location of casting codes on high-pressure USA engines.

Find and post here:
- Head casting code
- Head date casting code
- Block casting code
- Block date casting code