I am assuming that this is the same mounting arrangement as the engines in the 123 models. There should be three rubber mounts that are basically rubber cylinders with a stud at each end. You simply unscrew them from the manifold and screw in three new ones, then mount the air cleaner over them and replace the nuts. You should bend the oil drain tube around to a position where it will line up without putting a heavy sideload on your new mounts. This will make them last a long time. I would also recommend that you inspect the rubber sealing ring that fits to the underside of the air cleaner housing. If it is soft from oil or torn, replace it at the same time. These are important pieces for the health of your engine. If your air cleaner leaks at the base it will suck in dust which is really tough on your top piston rings.