Those aren't supposed to come out. They were installed with a jig to align with the camshaft and the bolt heads removed, so it would be nearly impossible without that jig to get one aligned properly in another block. If you really want it out, drill out the block with a bit that's larger than the bolt diameter till the bracket comes loose, then deal with the bolt stubs in the bracket if you're trying to save the bracket.
Or even easier, throw the bracket out with the block.
