Which spark plugs to use with a 97 whipple charged Yukon

[rushr]

As the title states.... I need to replace the plugs and wires and I'm having issues finding a solid answer, although I'm sure it is posted somewhere. I know I need to go with at least a one step colder plug, but when I talked to the guy at NAPA he said the system was already showing the AC Delco plug as the coldest. Does anyone have a recommendation of a plug to with...and the part number?

 

[rushr]

any suggestions?

 

[ChiTahoe]

I'm running NGK iridiums most of the guys will tell you to run the delco stock plug.

 

[rushr]

run the stock delco plug even with the supercharger? I always thought you should do a colder plug when boosted.

 

[SunlitComet]

AUtolite stock heat range plug copper core is 605. On step colder is copper core Autolite 104