3800 spark plug gap

[Buick 1]

I did a search but came up with nothing, so i'll just ask. What gap do most people run with 103 or the race plugs from ZZP when they have an aftermarket cam installed in their car. I order a set from ZZP and the 103 came gaped at .045 so i opened them to .056 and the car just doesn't run well on the top end. I thought maybe a change in the gap would help but i'd like a little feed back before i change any thing.

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[sr71_rgl]

Plug gap has a big influence on how the car will run. Especially when using colder than stock plugs. The 1st time I tried 103coppers I gapped 'em around .055 and the car ran like total crap...low end, high end all over the rpm range. I gapped 'em down to .045 and it ran like a top. YOu should choose plugs/gap according to boost. If you're running at 10psi or less 104s gapped around .055 will do well (and idle better than 103s). 10-12psi 103s gapped small (.045) will work and greater than 12psi 103s gapped a little larger to combat KR is recommended. I've heard some guys say gapping plugs to wide under high boost will blow out the spark but I think too wide of a plug gap at any boost will cause it to run like crap.