My Fairmont has had the same MSD 6T box mounted upside down behind the dash, screwed to the underside of the cowl. It has been there, and been trouble free for about 25 seasons of drag racing. In my 85 Mustang, I have had MSD 6AL boxes, mounted on the inner fender under the hood. I had 2 6ALs that failed, one was an electrical malfunction, not sure why the 2nd box went bad.