You know. This has been running circles in my head. This could be a stupid question so bare with me. Would Chrysler actually have two separate castings for the 318 and 360? Or would they share the same casting, and simply bore the block larger for the 360 mains and pistons? It doesn't make sense to have two separate castings. Now big blocks obviously have a low deck and a tall deck. Which you can't share intake manifolds due to this. But you can put a 318 intake ona 360 no problem. They are all the same deck height right?? With that being the case, the cylinder wall thickness would be the same. Basically just turning this 318 block in to a 360. Am I way off in my train of thought??? Open to debate!