As a general rule, C2AE (292) blocks are good for at least an 0.110” overbore but sonic testing needs to be performed simply to insure that core shift is not going to be an issue. Starting with the C2AE blocks, the 312 blocks were discontinued as being their own casting which left C2AE blocks being used when production runs of 312 blocks were required. For this reason, the run of the mill C2AE blocks typically have at least enough material cast in them to make a +060 over 312. But as I’ve mentioned, core shift is still something to watch for so sonic testing is how this is going to be determined besides knowing exactly how much cylinder wall thickness is available for boring.