bout-time

Ok, I have a stock 1992 LT1 Corvette. I installed Autolite Copper Core Resistor plugs and gapped them to .035 because that is what the Autolite website said for my application. I am still working on the car and have not fired it up yet. I noticed that the factory plugs are gapped at .050.

My question is, is the .035 gapping for the Autolites wrong? If so, what should I gap them to?

Thanks!

1963SS

For performance applications I believe that .010 less than the factory recommendation is fine. Remember, the factory establishes the gap based on available voltage, emissions longevity requirements, mileage and performance. For pure performance applications the smaller gap is better. Although less of the mixture is exposed to the spark the spark is hotter without needing a different heat range plug. That's a good thing. I'd go with .040.

bout-time

Ok, thanks for the reply. I guees I need to take the plugs out tomorrow and re-gap'em to .040.

HlhnEast

Are you saying the plugs you took out are gapped at .050? Some erosion of the plug electrodes is normal. Gunny has a good suggestion of a good compromise.

BADDUCK

.035 is fine.

1963SS

I agree. It's certainly not worth pulling the plugs for the little bit of difference.

navy_vette

It takes a lot of convincing to get me to pull the plugs. These headers don't make it much easier.

If your fuel is fully atomized, a smaller gap is fine. It will make a fatter, hotter spark. Less gap = less resistance. less resistance = more amperage. more amperage = bigger boom.

bout-time

When saying .050, I was referring to the GM sticker under the hood.

I did decide to keep the plugs at .035. Didn't feel like pulling all the plugs just to re-gap to .040.

Thanks for your help guys!

H P Bushrod

I'm running a set of Autolite 606's (copper core) in my '93. Can't remember what I gapped them at, but I have no problems with it running or starting.

JackDidley

Good decision.

bout-time

I just installed Autolite 106's. Wonder what the difference is between the 106 and the 606 plugs?

H P Bushrod

I'm curious too. I just went with the application that replaced the stock plug. I'm sure someone will chime in.

Phat98

I think the 606 is an Iridium tipped plug...I'll check when I get home.

bout-time

What's interesting is that on Autolite's website they list the 106's for the LT1 from 1992-1996, but list the gap as .035 for 1992 and the gap as .050 for 1993-1996.

As far as I know, 1992-1996 LT1's were identical.???

1963SS

A lot of folks I know, including me, use the Autolite 104's.

bout-time

I'm guessing you are not running a stock engine?

1963SS

Real good guess.

ScaryFast

Is that anything like my NGK TR35?