What do the Engine
Casting Numbers Tell?
Basic information about your jeep...

     Because the 134 cu. in. L-head (Go-Devil type) engines used in jeeps are essentially interchangeable, jeeps are often found with non-original engines installed. The casting numbers on an engine or block can be used to help determine what engine your vehicle has.   The casting numbers are part of the engine casting and are not stamped onto the metal of the block like a serial number. (See serial number page).  Generally, the block casting numbers are found on the right side of the engine block below the distributor. The block casting numbers are raised-not stamped. The head casting numbers are normally on the top of the head in the right front corner. Head casting numbers are either raised or recessed, but not stamped.
     It is helpful to know the casting number needed when searching for correct replacement blocks or heads for your MB or GPW.

Note: This table is under construction and may contain errors -(Ren Bernier, 12/9/02)
(Information contributed by Joe Potter, Alisdair Brass, Jon Rogers, Mark Tombleson, Jim Kilborn, Fred Coldwell and others.)

Vehicle Block# Head# Images of Casting Nos.
MB      1941-45 638632 639660  MB Engine     Late MB Head
GPW    1942-45 GPW 6015 6050 GPW Engine    GPW Head
CJ2A    1946-49 641087 (Very early blocks - 638632) 640161 CJ2A Engine     CJ2A Head
CJ3A    1950-53 641087 640161 CJ3A Engine     CJ3A Head
M38     1950-52 641087 through s/n MC74419
804380 after s/n MC74419
800376 M38 Engine      M38 Head


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