The 5 inch in-dash gauge case OD is approx 4.57" (4-9/16", 116mm) and the bezel OD is approx 5.0" (125mm). You want your hole size to be around 4.75" but anything between 4.6" and 4.9" is OK. Case depth is approx 1.75" not including the uclamp studs.

The 2-1/16" gauges have a case OD of approx 2-1/16" (52mm). The bezel OD is 2.25" (57mm). Case depth is approx 1.25" not including the uclamp studs. The uclamp studs are 0.75" long.

The 3-3/8" gauges have a case OD of approx 3-3/8" (86mm). The bezel OD is approx 3.75" (95mm). Case depth is approx 1.75" not including the uclamp studs. The uclamp studs are 1" long.

If you do not have an existing panel with these size holes you may need to modify your existing panel or purchase an aftermarket dash panel for your vehicle. We recommend checking with Classic Dash to see if they make a dash panel for your application. To find other manufacturers of after market dash panels do a Google search for "dash panel" plus the make and model of your vehicle, i.e. "dash panel for 1979 Camaro".