Attached are photos of where/how I mounted the tach. I just have it mounted with velcro tape. I didn't really want to drill holes in the dash. The wires are just run through the crack at the grill and then over to the left side through the firewall where the steering hydraulic hoses pass through. You can see where I attached the sensor to the fuel line. You have to sand the paint off the line prior to attaching the sensor. I sprayed everything grey after installing it. One of these days I may get around to drilling a small hole in the dash to pass the wires through - although I have had no problem with them running down the front of the dash. When I first installed it, I wanted to make sure it worked before I started drilling holes.
Ryan