I've looked in many posts, and have seen people recommending anywhere from .030 to .043 spark plug gap.

Some posted that Johnny Lightning recommends .030
Is this true? I would think if it is, he should have a pretty good handle on it.

What's the down side on a small gap?

I know a large gap can cause spark blow-out. I suppose a small gap could get fouled?

I will be changing to cooler plugs, which I need to gap.
Problem is, too many recommendations.

Don't want spark blow-out, don't want loading up.

 

It really all depends on the mods what to gap the plugs at. Bigger injectors, high boost applications require smaller gaps.

I feel .038 is fine for most trucks.

 

I have NGK TR6's and I gap them at .36-.38

I use that for a 2# and a 4#

-dennis