[leftybass209]

Yeah, that's a no go. If the numbers match, they either match that the block is a 402, or the motor is a 454 from a later truck. The 454 is as original to that truck as the rims and tires.

Edit: the 402 could have been bored but I don't know the calculations to come up with 454 cubic inches. I digress however, it would still be a 402 block.