gauge fitment
 

Do you think this gauge:
http://www.aircraftspruce.com/catalo...c/10-01274.jpg
listed as 4 electric instruments in one standard size 3-1/8" aircraft case would fit in the 3-1/8" hole of this standard/1302 left side panel:
http://content.madirect.com/img300/303685.jpg

If so, I would use the other two 2-1/16" holes for a tachometer and a voltmeter with oil pressure and oil temperature gauges on the right side.

By the way, I would get black panels. I just couldn't find a pic of one in black. ;)