The timing cover for LA engines will fit on a 5.2 (318) or 5.9 (360) Magnums, and then the accessories can be used from the LA donor. If you are planning on using a stock Magnum engine with a mechanical fuel pump, you will need a fuel pump eccentric adapter for the camshaft, available from Hughes Engines. Oil pan and oil pump pick up will be LA style, although I am not sure which pans fit a 63 Dart.