I have a bbc standard deck 4 bolt, 4.500 bore block, it needs a sleave in #2 cylinder. It comes with 8 aries blower pistons and one is beat up from a valve being dropped and you can probably get a spare from aries. It is clearenced for a 4.250 stroke crank and the pistons are for a standard length rod, could make a nice low budget 540cid, make me an offer and get it outta here.