my new 360...

You need a 360 pan, the 318 pan is different. The mount needs to be shimmed because the spacing between the lugs on the block is different. If you are switching the 273 parts onto a Magnum engine and plan to use your mechanical fuel pump you'll need a fuel pump extension for the camshaft in your Magnum engine. I know Hughes sells them, maybe Mancini & others have them too, not sure.