At the time of cranking (when the starter is operating), a separate wire gives the points the full 12 volts, bypassing the ballast resistor when you release the key from start to on, all the power to the points now has to flow. When you hook up your system, check whether the distributor requires a ballast resistor some - notably some of the mallory units - will have considerably shortened life if run with the full system voltage.
Route the other end of the wire to one terminal of the ballast resistor cut the wire, strip 1/2 inch of insulation and crimp on a terminal connect to the ballast resistor. It does not have a ballast resister now my buddy said it was running smoothly when he last started it last summer i picked up a new coil and it says use with primary resistance wire or external resistor i'm assuming they mean a ballast resistor i have looked up wiring diagrams online, and haven't seen any. How can the answer be improved.
An electrical ballast is a device placed in line with the load to limit the amount of current in an the ballast resistor gets hotter, its resistance goes up. Ballast resistor do i need it by how does it hook up to coil it is necessary because ignition coils are designed to step up battery voltage high. Set the ballast resistor up to the firewall and screw the clamps in place step 5: connect wires to positive strip the end of the positive wire from the ignition, and connect it to the positive end of the resistor. The ballast resistor carries to much currant install a bigger bulb if it still runs on go to radio shack and buy a tiny resistor and mount it in parallel with the bulb the light circuit only needs carry enough currant excite.
I have a 1987 mc with ford 351 if anyone could post some pics of how your ballast resistor is hooked up it would help me out big time when i bought the boat it was cracked and not hooked up. Of course if you have a 6 volt system, you do not need a ballast resistor and your starter would not have the b/r terminal you only need a ballast resistor if you have a 12 volt system and points my 68 corvette has a 'resistor wire vs a ballast resistordoes the same thingcuts the volts to the points to about 8 volts. I'm not all that up on 72's, but are you sure it's supposed to have a ballast resistor my 69 doesn't - the voltage drop to save the points during run mode was accomplished via other means - a resistance wire between the run terminal on the ignition switch and the feed to the coil.