if you fill the blocks, .140 is about the limit. you can put a 4.375 crank in them too and get more cubes that would make a 529, but you will hafta have custom pistons made as i don't think je stocks them that big. pretty sure they do at .125.
if you check je's website, or wiseco or whoever, they usually tell you the info that you need, bore size, rod length, stroke for the crank etc.