I emailed Autometer awhile back and they told me, 3 3/8 Speedo and Tach and 2 1/16 for the other gauges. The third large hole for an SS dash would stay empty. It looked like it was going to be pretty tough mounting the gauges. I ended up making my own insert. http://camnick.home.att.net/dash.htm
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!