Trim tag swapping

[Lynn]

As for the GM cars, I know of at least one company that offers tags on cars through the 1977 model year. Seeing that the specific engine designation is in the VIN from 72 on, seems very few of the post 71 cars would get a fake tag. Anyone ever see a post 71 GM car with a fake tag? I know this 71 model was recently sniffed out with a swapped tag: http://cgi.ebay.com/ebaymotors/ORIGINAL-...1QQcmdZViewItem

Also, what years did Ford and Chrysler start using a specific digit in the VIN to designate the engine?

Thanks.