One of my colleagues have a 1944 Willys MB with a CJ-3A engine:
Right hand side casting info: 641087-L-W12A N1-CR-N2
Serial number stamp on machined boss above water pump: 3J-124935
There is a thing I find a little strange though. I am normally a MB/GPW guy, so please bear with me here, if I am mistaken. As I understand, the later CJ-3A blocks had the reinforced web in the left hand side rear corner. The CJ-3A information Page http://www.cj3a.info/cj3a/date3a.htmsays:
Now, the engine in question does have the reinforced block, but its engine serial number is lower than the one specified as the first block with the reinforcement. Is there a possible mistake here?In 1952 the engine block was changed to one with a larger flange at the rear. The 1965 Service Manual states that this was done at engine serial number (3J)130859.
I would say my colleagues engine was produced in 1952, but I will appreciate any information that can narrow it down.