Apparently the aftermarket has gotten smart, and is using the same iron vane movement that the General started using quite a while ago. Never mind their hype, the reason is it is far cheaper to build a 270 degree movement this way. A custom integrated circuit had to be developed, to make this practical. The "down side" is, the needle stops in random directions when power is removed. I had problems with this type tach in my cars, finally tracked down the cause and a cure. You can read this story in my posts here, some pictures too. I am wondering if the aftermarket made the very same mistakes G did? Bruce Roe http://www.oldspower.com/vb/showthread.php?t=57832
