I've read many posts on this subject with discussions and opinions all over the place. Even though I don't have points, I want to offer some protection to my stock coil and ECU orange box, but also want to get a good spark while maintaining the factory ballast resistor look (ceramic block with metal strap). Does anyone make a BR with lower ohm resistance that looks close to factory correct? I'm only getting about 5.5 - 6 volts to my coil with an old, original BR and would like to maybe get the voltage up closer to 9 volts.
First thing would be to check the possible reasons for the voltage you're seeing.
The voltage on the coil side of the resistor will depend on the voltage on supply side (ignition).
So that's probably the first thing to check. Check it while the engine is running at idle and off idle - say 1250 rpm. At the same time check the voltage at the alternator output stud.
The voltage drop across a resistor will depend on the current running through it. So if for some reason the coil is drawing a lot of current, that's another possible reason.
Chrysler resistors should be checked for resistance at ambient temperature but were expected to have higher resistance when warm (low speed driving) and cool down a bit at higher speed (resulting in slightly lower resistance).
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If you are measuring .5 to .7 ohms, that's about right for most factory combinations.
Check the coil primary resistance too. That can affect the current draw and therefore was matched with the appropriate resistor.
Supplying higher voltage to the coil may or may not increase spark energy.
Higher voltage can be useful when there isn't time for a coil to get saturated before firing. Otherwise its just heating the coil up.
