I am getting ready to install these plugs on my 05 crew 5.3 and don't know what to gap them at. Could I get some suggestions on gap for best performance. I have a 89/93 performance w4m tune,k&n,cai and a 160 thermostat. Thanks ahead!

 

if you look under your hood it says .06". that is what my 2000 5.3 says.. but just check under your hood. im sure more guys will chime in..

 

Your supposed to gap them at .40
Only one type of plug that can come in them stock is to be gapped at .60 and thats the ngk/ac delco plug.All others gap at .40

 

Actually isnt the stock Plugs gaped at .45? Im pretty sure they are, only 03 and newer i think.Thats what the specs show.

 

Look at the manuel that comes with the truck.....one goes .60 the others go .40

 

My Owner's Manual for '03 Silverado calls for a gap of 0.060" for all engine options.

 

Thats because you have a HD 6.0L

 

Damn, looks like I got others confussed on the gap as well. Maybe the best gap for performance can be discussed further. I see .40 looks to be the winner right now. Don't know if anyone else has tried different than .40,if they have please chime in. I am going with .40 and maybe we can see if others have different gaps for different set ups. Thanks for all the help and lets keep the discussion going. Hopefully this will help someone else with a slightly different set up than mine. CYA!

 

I pulled out the stock plugs and checked thier gap before gaping my new ones and stock was .06

 

I know it was a typo but I don't want anyone else confused the gap size is in the Hundreths (decimal point than zero) eg: .040, .045, .060 of an inch.