I think I remember reading that the LS1 is only rebuildable for .005 over or something like that and then that is it. Is this the same with the 5.3L?[/b]
I don't know for sure exactly how much you can overbore the ls1 but the iron sleeves in the aluminun block are your limiting factor. Since the 5.3 is an iron block, you can safely overbore (up to a certain extent.) Hope this helps.