Its a very over used term IMHO. And its "true" application depends on the year in question and the person using the term Easy to ask "what do you mean by matching numbers?"
In 64-67 this "often" (in the narrowest terms) means that all of the parts on the car were made in a relative time period before the car was assemblied/built. If the model had a K code engine or 4 speed trans I would want to see a VIN on these two items
In 68-up I would include (with the above description) a partical VIN on all engines and 4 speeds (often automatics also)
Many of the cast (not all) and stamped parts can be coded to day they were made. The coding varies depending on what part it is. Some indicate the month, day and year while others indicate shift
Hope this helps. The subject always seems to bring about some discussion and it have been discussed on this board a number of times. Good luck with the car
Jeff Speegle
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