SIG sold aluminum mounts that were sort of a T shape that had a leg that attached to the fire wall and a leg that was 90 degrees to that on which the engine was mounted. These were sold in sets, and you spaced them as required so that they were kind of universal. SIG had the material custom extruded in that shape in long bars and them cut the mounts themselves and packaged them. If I remember correctly, they quit making them because something happened to the dies and the cost of replacing them was prohibitive so they went the plastic route like other manufacturers. Dubro makes something similar but it is engineered as a vibration absorbing mount, and comes in about 5 or 6 sizes. It's a die cast aluminum. Check out their web site for more information and specs.
Type at you later,
Dan McEntee