decoding 340 block numbers

Skep, I have been trying to do the same thing....I have a spare 340 block and the vin on the oil pan 0R126870....well that translates to the last 8 digits on the orig car vin. BUT its the 1st 5 digits on the car vin that gives car specific info(they dont put those 5 digits on the engine block that I know of)