Thanks all for your answers!

Regarding Timing light -- I just have a basic one -- no tach on it.

I suspect my old Sun tach is not accurate at higher RPMs, so wanted to hook up another to verify before yanking it out and discarding it. When I take off in the car (4speed w/ 4.10 gears in the rear), it feels like it's revving very high and I have to shift, but generally the tach is showing less than 2000 RPMs. So, I figured that can't be right..

So, it sounds like I can have two wires going to the negative side of the coil for the two tachs. I was just thinking that somehow they might interfere with each other, but it sounds like a lot of folks run this way already.

Thanks !