it's .005 i just say zero because thats easier. i used the kbs with 452 heads. later changed to eddy performer closed chamber, cut the heads to get my cr up. thats why i want to use the same block, heads and intake. 440 source list it at .025 in the hole, i guess thats on a stock/uncut block. thinking i will end up about the same as now so maybe my cr and piston to valve will not change.