vehicle identification

I have a conundrum. I would like to see what the popular take on a numbers matching car is. My father-in-law, an ol' skool hotrodder, once explained to me that a numbers matching car was a car built in the very late sixties to present and represented the start of automobile automation...

im trying to sort the paperwork on my 1951 pontiac chieftain, here in uk. Ive found the vin ok, but have a different number on some paperwork. Could that be data plate/ cowl plate/ body tags numbers? they are 06129fg042

so my buddy's heavy Chevy Chevelle has the vin 134371L144211 and the block has the number 3970010 on the back by the bell housing. Is there anyway this could be the stock motor? Any help would be great!

1977 Chevrolet C/K Series Truck: Identification and Smog Equipment Verification Hi All, I have a 1977 Chevrolet truck. It does not have a VIN plate on the driver-side dash nor does it have a data plate on the driver-side door jamb under the striker. In place of the data plate, there is an...