I didn't ask the weight of the block. It has to be heavier than a stock block because of siamese bores, thicker decks, and such. He said it would take a 4.25 bore and accept a 4.25 stroke. That's 482 cubes. Standard bore is like 4.07(?), I think. Probably finish hone to 4.09, which is std. bore 6.4.