Original type wiring harness with HEI

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Depending on what's happening you may have insufficient spark under load or acceleration or it could be as bad as strange running at idle due to very short spark duration (saw that one when HEI was connected to original resistance wire). The majority of conversions done using original gauge wiring don't display any noticeable issues but to me it only makes sense to wire it properly from the beginning rather than have to diagnose a problem after the fact.