Have been doing some testing of different ignition coils lately on the truck.
Here is my current favorite setup: Mopar Distributor with HEI conversion and the 60,000 volt E-Core Coil, running on straight 12 volt power with no ballast resistors. Also ran this same identical setup on the 1976 Dodge D100 that I previously owned.
Being that it is an E-Core Coil that pushes out 60,000 volts, was able to open the NGK GR4 Spark Plugs to a gap of .050 ths.
A longer spark ignites the air/fuel mixture in the combustion chamber better, more efficient burn. As shown by the clean burning GR4 spark plug below with the .050 gap at the electrode.
Nice clean burning plug, especially considering the original 318 Roller Engine has 96,000 miles on it. Running Non-Ethanol Fuel 91 Octane rating. Fed by an Edelbrock 1406 600 cfm 4 barrel carburetor.
The tailpipe is also running cleaner too with the .050 ths spark plug gaps.
Nice simple ignition setup that runs well.
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