Wally, I was wondering, what car is your tacho from? Now that I have a 911 tach in front of me, I realised yours looks more like a 911 unit than 914. I also found this website about the 914 tachometers, and yours doesnt seem to fit in that description:
http://www.p914.com/p914_gauges_tachs.htm
I'm curious if I could fit the 6cylinder tach on the 4cylinder engine (and make it show the real RPM).