I installed two gauges (one dual-channel CHT and one voltmeter) from Westach in a two-gauge panel in place of my ashtray. Voltmeter runs to switched power on the fuse panel.
My '75 with external voltage regulator doesn't appear to charge until ~1400 RPM. I don't worry about it too much; I've got a big battery and my 911 doesn't spend a lot of time at idle...
