So I called Mopar performance and these are the numbers I got. 68166434AD BARE BLOCK 68226133AA SHORT BLOCK These are warranty numbers and they won't release the item without a Vin. Searched the first number and nothing. The second is a 6.4 short block for a 2500 truck. My understanding is its the same block but machined differently. The short block you can purchase without a Vin. Matt