Good question, and one I'd be interested in knowing the answer to myself... My Deuce has points, but my Camaro has the "Pertronix" unit you describe, and I have never been able to get a SW 970 tach to do a darn thing in it... I have always blamed it on the tach itself, as I have tried several 990B monitors without luck... never thought about it, but maybe the problem is the ignition system, not the tach...
PS.. i just made this post because i wanted to use that new graemlin.
