Rule 1, don't replace the wires. They are not a wear item...The tip does wear and go bad, but they are replaceable. The wires you will get will not be as good as the OE. They are solid core.

You can't change the timing on a 420 so don't try. IT is computer controled and fired off of the crank.

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Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
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