ignition coil - ballast or no?

Did it ever occur to anyone to actually purchase a coil based on the year of the car?
The older form of ignition, by older that is referring to a Kettering style ignition that is one that used points. The ignition system was designed to be used in conjunction with a ballast resistance. That is either an external ballast resistor or a ballast resistance wire built into the wiring system of the car.
Generally that wire went from the ignition switch to the + terminal of the coil .
The resistance of either the external ballast resistor or that of the "ballast" wire was aprx. the value of the primary coil resistance or possibly the "impedance" of the coil
And a coil thus marked for that application would also say an external ballast resistor was required.
With the advent of a solid state ignition and there were various types they may or may not require a ballast resistance. Eventually that need for one was eliminated.
As were other characteristics of a kettering ignition.
Trying to second guess whether a ballast resistor is required with out knowing the characteristics of the ignition system and just holding a coil in your hands with marking on it is a bit like shooting at something in the dark.
AMC like many other manufacturers adapted the wiring of the car to what ever characteristics the ignitions system of choice was at the time.
The last time a kettering ignition was used was some where in the middle 70's. And I don't have all the manuals. But my '74 manual says that the coil MUST NOT have an internal resistance. There is a long torturous explanation of how things work which is typical of the era trying to explain something to an auto mechanic in the TSM as to how to trouble shoot the system with out really explaining anything other than DO NOT USE A COIL THAT HAS AN INTERNAL RESISTANCE. And a circuit explanation does not show a Pink wire. So using that is not a very valid approach to understanding what is going on.
Just a simple statement that all 8 and 6 cylinder motors use a coil that requires an external resistance.
The bottom line as far as I am concerned, is buy a coil based on the year of the car. And forget references to a pink wire unless you can confirm they actually mean something.
My 77 manual is equally as vague when it comes to technology but it clearly states that there is no primary circuit resistance wire or ballast resistor used. It also however shows no PINK wire as part of the wiring.

You will however depending on where you look, find references of pink wires going to the alternator. However if you don't know where to look or why it might be easy to confuse this with how the ignition works.

Frank pointed out that older Rambler or AMC products used an external ballast resistor which was industry standard pretty much
Some where in the late 60's AMC axed the ballast resistor and went to a wiring harness ballast wire. Some where in the middle 70's, 75 or 76 AMC was pretty much electronic ignition. Many if not most of that era simply had an electronic method to eliminate points and their adjustments. Largely to satisfy a federal edict that the ignition system run 50,000 mile with no maintenance required.
Coils may be marked as needing an external ballast. On AMC cars with a built in ballast wire, that is satisfied. So for those applications, do not use one that does not require an external ballast.   
As the 70's morphed into the 80's the electronic ignition system grew and developed it's own benefits and pretty much totally eliminated many functions the Kettering ignition. Also requiring changes in ignition wiring and distributor designs. And used coils called out as needed to make things work. So each year may require something different.

Edited by uncljohn - Oct/29/2015 at 10:37am

Just wondering - is there such a thing as a "parts list" for a 1958 Rambler American?

I found out a few things today. From the computer in the auto parts store a 58 Rambler takes a UC15 if it has Lucas ignition and a UC12 if it has Delco ignition. The T behind the P/N just designates economy series and yes, they do have made in China written on the coil.

The UC12 is slightly smaller in diameter than the UC15. I had to spread the bracket for the UC15 but the UC12 they gave me today slides right in, just like it was meant to. This and the fact that mine did not run with the UC15 sort of tells me that I may need the UC12 and I was told they sell a lot of them.

 

Now there is a counter guy we could all use! Pretty little car and glad to hear that she is running healthy.

If you have an O'Reilly Auto Parts in your area, get part number 2-5025. It's a 12volt coil and does not require an external resistor. Also, it has a lifetime warranty and should have "External resistor not required" printed on the coil.