If you're buying new,pretty much any tach should work fine for you. I have a a Faria tach in my '74 Chevy truck that only works with a V-8,and a couple of 1980's (?) SunPro tachs I'm using on my older trucks;they're adjustable for a 4,6 or 8 cylinder engine,will work with points or HEI ignition. Don't know if they work on six volts (I remember seeing that mentioned on one of the truck forums recently), or how to set up for positive ground,but SunPro's Tech line people could likely answer that for you. These tachs sell for 50-60 bucks at most parts stores.
Speed
