Engine Block Casting Number - 3970010
1972, 350 cid engine block with 2 or 4 bolt main caps.  The casting number is mainly for identification and quality-control purposes.  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. The casting number also identifies specific "families" of components.  The casting number is located on the transmission mounting flange at the rear of the block on the driver's side.

Engine Block ID Number- V1209TDJ
      V =  Flint Engine Plant
     12 = December
     09 = 9th day of month
      T  = Truck
     DJ = 1972, 350cid, 175hp, 4 barrel
The ID number is stamped on the engine at the the engine assembly plant and identifies the date of assembly, the displacement/horsepower combination, and what chassis it was to be installed in.  The ID code is located on a pad just forward of the passenger side cylinder head.

Engine Block Date Code - L41
     L41 = December 4, 1971
The date code is located on the transmission mounting flange at the rear of the block on the passenger's side and designates the month, day, and year the engine block was cast.  If the casting date is later than the assembly date (Block ID Number), then you know something is amiss -- it's real tough to assemble an engine before the block is cast.

Cylinder Head Casting Number - 3973487X
1972, 350cid, LT-1 engine with 2.02" exhaust and 1.60" intake valves, and 76CC combustion chambers.  The cylinder head casting number is found underneath the rocker cover, between rocker arm pedestals. 

Cylinder Head Date Codes - K261 and L81
     K261 = November 26, 1971
     L81 - December 8, 1971
Seems odd, but the two heads were cast in different months.  Guess they just grabbed whatever was on the self when they assembled the engine.  The date code is found underneath the rocker cover, between rocker arm pedestals and next to the casting number.  

Intake Manifold Casting Number - 6263751
Cast iron intake for 1972, 350cid/175hp engine with 4 barrel Rochester Qjet carburetor.   The intake manifold casting number code is located on top of the intake.

Intake Manifold Date Code - L61
     L61 = December 6, 1971
The intake manifold date code code is located on top of the intake next to the intake manifold casting number.

 

Exhaust Manifold Casting Number - LH:	3932489
RH:	3905365
The casting numbers on the Ram horn manifolds are on the outside near the 1-3 or 6-8 cylinders.  So far, I haven't been able to find a decoder for these numbers.  I know the right hand manifold is not the original because it has holes for emission tubes which are capped off with pipe plugs.  I'll keep looking for information on the codes and post when I find something.

Carburetor ID Number - 7042210
     70 = Rochester Prefix Code
       4 = Decade (1970-1975)
       2 = Year (1972)
       2 = Quadrajet, 4 barrel,
              Federal Standards
       1 = Division (Chevrolet)
       0 = Transmission (Even
              number is automatic)
The ID number is on the carburetor body on the drivers side behind the secondary throttle lever.

Carburetor Date Code - 3401
     3401 = December 6, 1971
The date code is found on the carburetor body on the drivers side behind the secondary throttle lever, adjacent to the ID number.