Date coding explained

[TwoTees]

As before trying to match cast dates is really a folly. You are much better off trying to match engines numbers with cars around it or match your original engine number as close as possible.

From your data can you tell how the engine numbers ran and were distributed between plants?

As you say the cast date may be close but if the engine came in a car from a different plant would the engine number be way off for that VIN?
(with VIN I mean the collection of other properties for that build)