1957 Cadillac Ballast Resistor??

[DTBass]

I am currently installing a Pertronix Ignitor in my '57 Coupe.  My question(s) is this.  Is there a ballast resistor in the electrical circuit?  The instructions for the Pertronix state that if the vehicle has a primary ballast resistor that the red wire from the Ignitor should be attached to the ignition side of this ballast resistor.  I don't see any type of ballast resistor on the car now but it was not complete when I bought it and I have replaced the original 365 motor with a 1962 390 block.  I have a shop manual that refers to a "resistor" connected with the ignition coil primary circuit to limit current through the ignition points.  Could this be what Pertronix is refering to as a "ballast resistor" ??  In any case I can't find this resistor or any other resistor, where would it be located on the car?  Any help would be appreciated, Thanks

[TJ Hopland]

They are all talking about the same thing.  If the system was running on points there has to be one somewhere otherwise the points would only last for 100's of miles vs 1000's and if you ever left the key on with out the engine running your coil would last a few minutes.

The typical resistor was a ceramic block about 4" long.  Later years they use a special piece of wire that had the resistance built into it.  Later aftermarket coils could have had the resistor built in.    Have a look at the coil, often times they will say something like 'use with external resistor' if they dont have it built in.

[DTBass]

OK, Well I looked at the original coil and it is a Delco-Remy type but all I can see besides that is the positive and negative markings, nothing that would indicate if it has an internal resistor.  It has what looks like a condenser mounted to the side of the coil going to the positve terminal.  This just brings up more questions like what is that condensor for and do I need that on the new coil?  Furthermore when I purchased the Pertronix kit it came with a new coil so I wasn't planning on using this old coil anyway.  The new coil has no markings that would indicate whether it needs an external resistor or not.   I don't see on the firewall or anywhere else anything that looks like a typical ballast resistor.  I will call the Pertronix help line on Tuesday but I really wanted to get going on this over the week-end

[Walter Youshock]

The ballast resistor is on the cowl just to the passenger side.  It is the ceramic rectangle thing.  There are wires going to a top and bottom terminal. 

The one on the driver's side is the heater resistor.

[Coupe]

Here's a pic I took during the tear down of my '57. Not very good but the best I have. My car is in storage for the winter or I would have taken a better one. I have the Pertronix set up in mine,  for originality I left the ballast resistor in place and wired thru it on the back side.

[DTBass]

Thank you very much Walter and Paul.  Yes it is on the firewall right where it was stated and pictured.  My eyes are not what they used to be.  Thanks again.

[greybeard]

The only thing I would add is to look for a second wire to the input side of the coil.  On some years of GM cars they added a 12V lead from the "start" position on the ignition directly to the coil to assist the starting of the car.  When the key returns to the "run" position, power goes through the dropping resistor to protect the points.
Good Luck,
Don, Campbell, CA