Chrysler didn't put VIN numbers on the engine blocks and transmissions until 1968 that matched the VIN # on the dash. Prior to 1968 the engine block just had a date code. So if anyone is selling a pre 1968 numbers matching Chrysler, then the seller either:
1) Paid too much for it since he/she fell for that when he/she bought it
or
2) Is trying to get premium for it when there is no premium to be had.
