Any ign system that uses a bal res [ & Mopar does ] is not going to produce as much spark energy as an ign system that uses an E core coil without a bal res. It is that simple.
And the numbers tell the story.......
GM HEI engines had spark plug gaps as large as 0.080". Mopar had 0.035". The HEI has enough 'oomph' to fire a big gap & supply it with a big current.
Testing done by D.Vizard on HEI in his SBC book, SAbooks #57, found that the stock GM coil & module ran out of spark around 4800 rpm buuuuuuuuuuuuuut, it was an unrealistic test as he admits because the spark was pumped into a chamber at 142 psi of pure nitrogen. An MSD 4 pin HEI module went to 8500 rpm [ limit of the test rig ] without misfire.
A good hi output module such as the MSD # 8364, Pertronix #D2000, Summit #850100 with a good E core coil such as the MSD #8207 or Summit # 850500 will get the job done. Use spiral wound HT leads.
