Chevrolet Engines

Engine Code Stamping Numbers
All engines are stamped with an engine ID code, consisting of assembly plant code, production date and suffix code. V8 codes are stamped on a pad just forward of the right side (passenger) cylinder head. 6 cylinder engines are stamped on the passenger side of the block behind the distributor.
The engine date must precede the car build date, otherwise something is amiss. Some engine machining operations (decking) will obliterate the engine ID.

Engine ID Code Example: V0101CLJ - (V = Plant, 01 = Month, 01 = Day, CLJ = Engine Suffix Code)

Engine Plant Code
Flint (Motor/6-cyl)  F
Hydramatic  H
St. Catherines, Ontario K
(McKinnon Industries Canada)
GM of Mexico  M
Saginaw Service S
Tonawanda  T
Flint (Engine/V8) V

Casting Clock
On some Saginaw blocks, intakes and exhausts a "clock" was cast into the block. The clock is a circle of 10 dots, one dot for each hour of a shift (usually 10 hour shifts). An arrow points to the beginning of the shift an another dot outside the circle indicates what time of day the cast part was made.
Through the casting date, the day/night shift indicator and, on some components, the "clock" position, it's possible for Chevrolet to pinpoint within an hour or so when a specific component was cast. Casting numbers also identify specific "families" of components

Chevrolet Engines References / Casting Numbers
Exhaust Manifolds Engine Block Casting Number Locations
Machine Shop Block Casting Numbers
  Big Block History and Identification
  Cylinder Head Casting Numbers