[mickmate]

The windsor engines were compact, revolutionary light weight castings in their time. Consequently the cylinder walls were thin. The core shift can be visually seen on the underside of the bores as a lip that varies quite dramatically in wall thickness from one side to the other. I had a bore crack up a 302W cylinder and you couldn't see it. The engine constantly overheated and drank or puked coolant. As mentioned sonic testing is the only way to tell. The other thing to watch on old engines that has a similar effect to core shifts is leaving them for years partially filled with liquid (like rain) and they rust through from the back.
Cheers Nick