BTW, Im pretty sure you cannot "bore" a 402 to get a 454.
The 396 has a unique small bore block and a short stroke crank shared with the 427 (internall balanced). The 427 uses the 396 crank and shares the large bore block with the 454. The 454 uses the 427 large bore block and adds a long stroke crank (externally balanced and unique to the 454).
So neither the block nor the crank from the 402 (396) should be able to build 454 ci.
Not sure I would trust this guy's mechanical savvy. If it is really bored that big, I would suspect holes in the cylinder walls
BTW, if this car doesn't go past $13000, I'll buy it and let my wife have it.