ReGap Factory plugs to .050 from .060

Tucson_02Silverado · November 25, 2002

Has anyone regapped the stock plugs to .050?

When researching for the AC Delco Rapidfire plug to use in the 5.3L (#12), the stock plug is an NGK OEM number with a basic description of TR5 OEM platinum. If you match the description with NGK's standard part numbers, the OEM plugs translate to TR55vx. The OEM plugs are gapped .060 and those who have dumped the OEM plugs for NGK TR55 gap them at .050. The NGK's in the LS1 type engines would have a different number since NGK is custom sourcing them to GM gapped at .060 and not the TR55vx at .059

By the NGK's basic description, I would think this would be a Free Mod.

CMNTMXR81 · December 2, 2002

I went .050 on mine. FYI, the only difference I believe between the TR55's and the TR55vx's are that the Vx's are platinum. I have TR55's in my LS1 @ .050.

Some guys I know went .040, but I didn't want to go that extreme. GM gaps them at .060 for a reason, a larger flame kernal I believe. But going smaller allows for a stronger kernal. So by only dropping it a .010 still allows for a large kernal that is a little stronger.