I have a 2002 5.3 litre Chevy. The book says the spark plug gap is to be .060 but the guy at the Chevy garage said he thought that there was a bulliten out that the gap should be .045.

What the truth?

 

I gap my ngk's at .060". Runs smooth. As long as it keeps running smooth I'm gonna stick with .060".

 

It all depends which plugs you're using, and if you're N/A or F/I. Stock gap for the platinums is .060. The Delco Iridiums should be pre-gapped at .045. I keep my NGK TR55's at .055 which is straight out of the box. Alot of FI guys run NGK TR6's at .030 to .035 I believe.

 

Yup I just installed the TR55's tonight and they are pre-gapped at .055 which is where I left them. Runs pretty dam good too!

 

NGK TR55 are pre gapped at .059" according to the NGK part # key. The first 5 is the heat range and the second five is the gap. This series of plugs have a heat rating of 4 (hot) to 6 (cold) so 5 is in the middle and gaps of None = .039" ( ex TR6 ); 5 = .059" and 0 = .080".I noticed the TR6s I installed were a very loose .035" when I installed them but they were close so I left them. I tried adjusting one but it was a real pain for the small difference so I left the rest and adjusted the other one back to the factory setting.

 

i pulled my stockers out today to get ready for the radix and just for the hell of it i checked them... at 5000 miles....35 is what i got

 

I'm running AC's just like the stock plugs but with the Radix which is being installed now. Nelson tune to come after the Radix is up and running. Will Allen recommend a different plug maybe?

 

ngk tr6 at 35.spark will blow out on stockers.....

 

I believe Allen will recommend the NGK TR6 gapped at .035 along with most other people. I see that BigTex is using the Iridium IX version of the NGK and seems to be having good luck with them.

 

The stockers in the Avalanche are gapped at .035 from the factory for '05 ???? That seems weird because the stock gap is .060 on all the Silverados for '03 from the 4300 right up to the 8100 according to my Owner's Manual. Something new?