[bobdylan]

Thunder v12's site mentions that there are two different v12 blocks, and not all parts interchange, I checked casting numbers on 10 blocks 9-2458808 1- 236728 I am curious about what the casting numbers of other blocks are, and what the difference is, I thought the serial number might be a clue, but the block that is different does not have a serial number, the block must of been decked at some point. Casting number is on the back of the block below the head on the same side as serial number. Thanks. Bob