The 05-08 hemis are a .045 gap and the 09-10 hemis are a .040 gap. According to WKJeeps.com


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Won't hurt a thing if they're run at .044, .045 or .040 in.

 

I've seen every gap from 0.040" to 0.045" for this generation 5.7L HEMI. My '08 is quoted at 0.043" in both the owner's manual and the MOPAR factory shop manual. This works out well because my Bosch spark plug gauge has a 0.043" diameter wire in it.....so that's my number.

I think more importantly, you should check the gap on each plug as you put it in. I know that plug mfgrs tout that they are properly gapped at the time of manufacture. However, they can be jostled around in handling afterwards.

My typical experience has been 10 of the 16 spark plugs I buy are not correctly gapped. I have put in 5 sets of plugs and had no issues.

There are 2 other anal things I do with spark plugs in the HEMI:

• Check every new Champion plug for the correct black top on the upper electrode before I leave the store. There are silver-tipped ones with the same number and they will cause you to stall. There is a L-O-N-G thread on this (Charles R. Shell started it). Don't think NGK has had this issue with their copper core spark plugs.
• Tag each plug as it comes out of the engine with the cyl# & position (eg, 6 Front or 5Rear) so I can "read" them later

 

I've seen every gap from 0.040" to 0.045" for this generation 5.7L HEMI. My '08 is quoted at 0.043" in both the owner's manual and the MOPAR factory shop manual. This works out well because my Bosch spark plug gauge has a 0.043" diameter wire in it.....so that's my number.

I think more importantly, you should check the gap on each plug as you put it in. I know that plug mfgrs tout that they are properly gapped at the time of manufacture. However, they can be jostled around in handling afterwards.

My typical experience has been 10 of the 16 spark plugs I buy are not correctly gapped. I have put in 5 sets of plugs and had no issues.

There are 2 other anal things I do with spark plugs in the HEMI:

[*]Check every new Champion plug for the correct black top on the upper electrode before I leave the store. There are silver-tipped ones with the same number and they will cause you to stall. There is a L-O-N-G thread on this (Charles R. Shell started it). Don't think NGK has had this issue with their copper core spark plugs.
[*]Tag each plug as it comes out of the engine with the cyl# & position (eg, 6 Front or 5Rear) so I can "read" them later

i went with with ngks as well, all gapped at .44 right out the box. checked them all.

 

getting ready to install mine tomorrow, just tackled a leaking radiator. what a PITA. i always check gap before i install, hopefully no issues.