Dating jeep cj5
The commonly accepted description of the CJ-3A seems to apply only to the mid production vehicles.
Unlike modern vehicles, the difference between CJ models was not distinct.
This "skew" is probably due to engines being pulled from stock for other uses, such as replacement engines.
Existing original CJ-3A engine serial numbers initially increase as expected, but then in 19 the skew becomes negative by approximately 2000.
Then in 19 the engine numbers climb again as expected.
The negative skew would indicate there are fewer engines than vehicles.