OP here - we had the old style Ford dash; here's where I mounted the ScanGauge:
I used sticky back velcro for both installations. I can get stuff to stick to the black plastic on the Chevy after cleaning with acetone (careful! It'll melt some plastics!), but the tan textured plastic is anti-sticky....
There's a data port on both the right end and the center back of the ScanGauge, so if you want a clean mount, you could drill a hole in the dash & hide the data cable. It is a standard RJ45 ethernet style plug.