Carry a spare coil if using Pertronix in a hot environment. They have been known to open when too hot. You just have to sit around for awhile to cool down. I always had a copy of LCM in the car.
Just got the relay for Christmasfrom my wife so will be installing it this weekend if the weather holds out.
Going through some of these older threads and found this one to be useful.
I’m swapping out my carb for a new Holley two barrel (0-80500), and was looking for a 12v switched power source for the choke. In looking things over, I found the previous owner installed a Pertronix unit, but connected to the coil instead of a 12v switched source.
Looks like I will install a relay triggered from the coil or ignition switch (red/green wire from c post), to power the electric choke and Pertronix.