69 Barracuda tach

Did you open up the tach?

The blue is +12v ACC power. The gray Is -coil. Mine had on the inside red+ and white points. It never pegged like you are saying but did not sweep correctly with the electronic ignition. It would seem fine at idle put did not respond well with throttle. The Tach may be toast and changing the board may not help it!

Seems like a crap shoot for $100 bucks. Points should work just fine with the original regardless of the coil used.