Hi Rich , correct data , however the DC resistance of the ignition coil ohms is in series with the ballast , lowering the current ; .6 ohm in 12 v would be 20 A , and your 10 A number probably assumes about .6 for the coil , about right .
-- However at idle the dwell time closed ( time per spark — not degrees) is very long , the coil saturates and the current rises , per spark , the ballast gets hot and current drops a lot to protect points and coil . Especially if ignition is on motor not running points closed (!) . That situation pops a marginal ballast. This is why you should never put a “ high performance “ coil on the car without knowing the resistance of the new coil primary . Low aftermarket ohms , in an attempt to get hotter spark , will burn out ballast and burn points . And not give you a hotter spark either . It is well designed , just as it is . What helps with a hotter spark is more angular dwell at high rpm , why mopar dual points . That second set closes early , single point you have to wait to close as it goes over bump of cam , translates to maybe 15-20 % more time to “fill up “ the coil magnetic field , a fixed time set by physical coil L / R ratio —- on the order of 2-3 milliseconds . So that dual point gives you 15-20 % more rpm before the same spark fade ( % varies , just an example ) . Direct AB comparison of 300B distributor on a 354 on dyno vs best MSD made showed zero difference in HP ( 600$?— for what ? more troubles?) , at 5800 rpm . I saw this personally only because MSD failed on the dyno tun . … as they are prone to do in cars too) ; guy who owns dyno said “I see that all the time” . A curse for Chevy guys .., They DO see better with MSD , right up there with stock mopar . We adjust points and keep going just like new They were ok for Petty at Nascar , ok for me too . Very fussy to get right you need a dwell meter . Agree too , ballast is either ok or dead , rarely would come and go . That is typical of capacitor , which then gives a very weak spark . jg Sent from my iPhone On Aug 15, 2023, at 8:56 PM, 'John W Sager' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx> wrote:
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