Need casting number DECODE

[guywmustang]

I have a 66 Mustang with a motor that is not original to the car.

This casting number was found behind the intake manifold on the top of the engine. The number found was: 7R121602

I would appreciate if someone could help me decode this. Thanks!

 

[Max Power]

Doesn't look like a Ford part number to me.

 

[Ronstang]

Pictures would help....that number alone means nothing at all to me.

 

[Max Power]

I believe the engine number is on the skirt of the block by the motor mounts. It will probably start with a C or a D or an E.

 

[TobyGaff]

The casting numbers for the engine will be on the bottom of the block just above the starter. You will probably have to take the starter off to clean and read the numbers.

The numbers that you are looking at I believe tell the plant, and the production line that made the block originally. The engine casting numbers on the bottom of the block tell what casting design was used. These are the numbers you are interested in. Occassionally they are also on the drivers side front of the block just below the head, but not all blocks have them there.