[Vhp04]

I got A little over 1,000 rwhp, and I just put this NGK 6510 spark plugs but they came at .040 is that good or should I close them down a bit. want my car to be running the way it should it won’t hurt it if I leave it how they came?

[Camaro1973]

Originally Posted by Vhp04

I got A little over 1,000 rwhp, and I just put this NGK 6510 spark plugs but they came at .040 is that good or should I close them down a bit. want my car to be running the way it should it won’t hurt it if I leave it how they came?

Depends on your boost bud. If over 15lbs of boost gap them at .028

[CW3SF]

What about for a ported stock blower at say 10–12 lbs of boost? .032ish?

[radz28]

I think JRE's been pushing around .040" for up to that boost.

I'm at about 700, and just put in 6509s, and with about 15-lbs, and .040", it sure is snappy.

[Camaro1973]

Originally Posted by radz28

I think JRE's been pushing around .040" for up to that boost.

I'm at about 700, and just put in 6509s, and with about 15-lbs, and .040", it sure is snappy.

It’s not going to make anymore power or run better at .040. I can’t run .040 on mine, I tried once, misfires once it gets close to 15psi. The coils/wires etc have enough voltage to jump the gap but blowout becomes an issue.

[radz28]

Originally Posted by Camaro1973

It’s not going to make anymore power or run better at .040, a burn is a burn. I can’t run .040 on mine, I tried once, misfires once it gets close to 15psi.

I'm only offering what's been posted here, as best as I can remember, and my experience. You're making a lot more power than I, so I don't know that I would be surprised by your experience. I'm certainly no expert

[Camaro1973]

Originally Posted by CW3SF

What about for a ported stock blower at say 10–12 lbs of boost? .032ish?

A safe bet IMO would be .032 . It’s not worth risking spark blowout at .040, esp with no difference except a possible smoother idle.

[Camaro1973]

Originally Posted by radz28

I'm only offering what's been posted here, as best as I can remember, and my experience. You're making a lot more power than I, so I don't know that I would be surprised by your experience. I'm certainly no expert

I mean if the car is mostly stock esp with no cam running the highest gap is mainly better for idle. I’ve seen no performance improvements with a larger gap.

Basically you want to run the largest gap you can without spark blowout.

Stockish 9-11 psi is good for .040
Modded 12- 13 I like 0.32
14-17 I like 0.28

This is JMO but I think these gaps work best.