Good thought. The resistor wire actually reducing the voltage when the car is running. Another wire comes to to the coil to provide more voltage when cranking. If the resistor wire was replaced with a standard wire at some point than that could definitely be prematurely wearing points and throwing the dwell off.

Jason

Interesting Jason. I'm going to have to look at that !!!! Thanks ROB

I ran a 396 with points in my Chevelle years ago...added an Accel coil and ran a Chrysler style ballast resistor in the wire.
that eliminated my problems and I always carried a spare in the glovebox.
you could try one to see if it helps..

You state that the points always look new when the failure happens. Using a full 12 volt wire would badly pit the points. You can verify the original low voltage wire by the woven fabric on it at the coil plus terminal.

It could, also, be the condenser failing and shorting out. Are you installing the separate condenser and points, or the uni-points with attached condenser. I don't know if the the uni-points are even made anymore, as they were notoriously famous for premature failure.
Also, make certain the distributor point plate has a good ground to the distributor body and the body has a good ground to the engine thru the clamp and bolt. A bad ground could overheat the condenser and cause it to fail.

What others are mentioning is easy to test.

While the car is running just check voltage at the coil. Should see roughly 9 volts or so. If you see a full 12 or more that may be your issue.

Since you mentioned you've had this car running for the last 12 years without an issue and this just recently cropped up, My guess is the problem is elsewhere.

Pertronix and done... If you weren't Day 2 etc., I'd say leave it points. I've been running a set in my 69 for the past five years. Not so much as a hiccup from them. I use a factory distributor. You'd only notice if you took the cap off. Hardest part of the install is having to run a full 12v versus the factory resistor wire. Very easy...

Isn't the Pertronix a two-wire setup? Maybe they changed. The Breakerless SE http://www.breakerless.com/
was the only single wire points replacement I was aware of.

I'm using separate condsenor. I have been changing them both when the issues start. ROB