How much does larger spark plug gaps affect driveability? Does it give a larger spark.

I would go with the MSD also. Mainly because it is so tunable.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

I have run mine with gaps from .030" to .065" and there was no difference.
True dat!

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Official Cookie and Mater Tormentor.

More reliably complete combustion. Tends to give easier starting, a smoother idle, slightly better fuel economy and can slightly improve performance. It's not a make-or-break-the-car's-performance kind of deal, but it does have a real and measurable effect.

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