Assuming no stroker crank, that's a bore of 4.62", compared to 4.00" stock. This is a real problem for an engine with 4.4" bore centers!
Try going to a machine shop and ask them for a .62 over-bore. That would be 466ci on a 350 with stock crank. Actually, there would be no displacement as each bank of cylinders would be siamesed together. Even if it was bored 0.1" over, it would require the stroke to go from 3.48" (stock) to 4.4"!
So either he's crazy or he means an engine swap, not bore.