Plug the bolt hold between the ports with a setscrew, use silicone over the screw and use a high performance gasket. Either trim the intake where the bolt above the port was or use two valve cover gaskets to prevent interference. This works great. Valve springs for 340 hp same as small-block Chevy. However, high performance springs are NOT interchangeable with big-block Chevy springs which are longer.
Oil pump is small block.
Oil pump shaft is big block. Rod bearings are big block. Fuel pump plate is small block. Fuel pump is small block. Timing cover seal is small block.