For what it’s worth, I was a mechanic in a Chevrolet dealership during the 1990’s. I’ve seen plenty of Delco coils that would not work in cold weather, but worked fine as soon as you warmed them up a bit. It sounds like Bubba has a bunch of experience with these things. Personally I would heed his advice and just install a new Bosch coil. That could very likely fix your problem. I’m reading this thread with interest, as I just installed a Pertronix ignition on my rod as well. I’m hoping it lasts more than 3500 miles.