[Hutch]

Nima
There are usually two sets of numbers on this pad in front of the passenger side head.
One set will tell you what type of vehicle the motor originally was in. If it starts with a T then it is a truck motor, if it starts with a C then a car motor.
The second set will contain a partial VIN to tie it to a specific vehicle.

In a lot of cases these numbers are gone due to the fact that the block has been machined or shaved at some point in its life.

These are good blocks some are 2 bolt mains and other are 4 bolt mains. You will have to drop the pan to figure this out.