Don't beat on that 440 block to much, all the 440 blocks have thin main webs,they break easily under detonation None of the 400 blocks have thin main webs Espcially the thicker main webbed cold weather blocks, but they do have some thin cyinder walls in some blocks Have your 400 block sonic tested before putting any money towards building it, I had one split a cylinder wall on the dyno during testing Test it first