About as close as you will get to having matching numbers (numbers matching) is correct casting codes for that year, and an engine serial number for that year and model of truck. This is not the same as when collectors talk about matching numbers/codes for a vehicle where some or all the codes are unique to the vehicle (or, for a vehicle where the manufacturer keeps/kept or published/published a book of official codes for a specific VID/VIN).
For our trucks, any date casting codes, if available (body, engine, head, block, transmission, rear-end), should be in proper sequence. If the VID (cab/body/frame ID/serial-number) has a date (usually on a plate on our trucks) that date should be a newer date than the date on an engine, transmission or rear-end (they would have to have been made before the truck was assembled).
http://en.wikipedia.org/wiki/Number_matchinghttp://www.lasvegasclassiccars.com/language.php#1
