It is also easy to construct custom aircleaners from aluminum sheet. I've built a couple by going to the K&N website and picking out a convenient size. Because the circular elements can be deformed to any shape, you can pick a shape that works for your carbs and installation space. Cut out matching top and bottom sheets, put on some L-brackets to locate the inside of the element with pop-rivets, and clamp the element between the top and bottom sheets. Highway signs are on tempered aluminum blanks which are stiff and durable, and are usually available used from the local street department. While this is not the most elegant approach, it can look decent if polished.
