new mystery

The casting date on a Mopar block is usually six months before the block was machined and assembled. It was '68 before MaMopar ever put VINs on the engines and transmissions. Having said that, I would say that you have a warranty replacement block in the car. The time frame matches a new car that blew an engine under warranty, and you have no VIN stamping. Wonder how much rubber they managed to lay before it blew?