I added a 4th gauge to my ashtray as I do not smoke and never use it for anything. I fabbed a small braket out of light gauge metal so that it would slide just inside the ashtray, then carefully drilled and bolted the bracket to the ashtray and fastened the gauge to the braket. I drilled a large enough hole through the back to run my fuel pressure line to connect to the gauge. The gauge I used was a cheap one and it didnt even have a light so I was able to take advantage of the light in the ashtray it lights the gauge up quite well at night. I can take some pictures of it if itss something you would be interested in.