Two different ballasts the one on the left is a 2095501 .5-.6 ohm the one on the right is a 2275590 a bit higher ohm I believe for the HP Cuda GTX Roadrunner Hemi Six Pack cars think it is .6-.8 ohm. either works fine with points cars. Your FSM has the listing in it for which ballast resistor and values it should be for your car. Now that is all factory coils, aftermarket you need to read the instructions on what they recommened. Dont get me wrong just about andy ballast will make your car run, but if it is not matchd you will not get the optimum results from the ignition system.
Yes, one MUST optimize the impedance of the ballast resistor with the coil one runs! I'm very pleased to note that when my 383 is cold, the combination of the current BR with that Taylor coil initially permits ~ 12/13 of the voltage division to be over the coil, allowing a high secondary voltage to quickly warm the engine up. Once warm, I note that coil voltage drops to ~ 9-11 VDC, implying that the BR accounts for about 1/4 of the circuit impedance.
I will shop for a good couple ballast resistors, one for now, and another as reserve for this coil. I like enough voltage to ignite and thoroughly burn the fuel on the power stroke, but not so much as to prematurely destroy the points.
A NASTY backfire into a boiling carburetor a couple weeks ago brought on my recent, more detailed tune up, with the extra research on impedance selection. With ambient temperature around 105F, I'd stopped at a Circle Jerk to purchase edible garbage for my spawn, permitting the contents of the carb bowl ample time to boil with "heat soak," resulting in a conflagration of several minutes duration upon attempting to start the engine. The ABSURD "safety wrapping" of the damned fire extinguisher exacerbated the fire and resultant damage, by delaying me over a minute!
Anyway, I WAS able to drive us home after a few minutes of carefully inspecting the wiring harness, finding a short where the insulation to my coil's primary supply which I neatly cut out of the wiring, and then bound, and shrink wrapped in situ. The coil itself, though heated considerably by the conflagration has continued to function, and this is what inspired me to measure the impedances and drops on the circuit elements, both while active and off. I already obtained a venerable NOS Delco U500, pre-UPC vintage as a replacment candidate for the coil, though I may shop for an epoxy filled Taylor Vertex coil, when I can catch them for under $40, inc. S&H ....
I might ping you for a coil or 2 also, later. Your store stocks well. Hmm, maybe some Oilite bushings also....
