I have not officially put them into my chevelle yet (though they are purchased and sitting on the shelf) but horsepower did a bang for the buck bit on these plugs specifically verses a double platinum & showed the dyno results of 5 or 6 (I cant remember specifically) horse & a 8% gain in mileage, so that was enough to convince me, the motor was the same from both sets of plugs, so nothing changed but the plugs. I'm putting mine in an L92 6.2L ls engine.

 

And did the plug manufacturer sponsor that show?

 

I had them in my 396 but i had trouble with glazing, i think the problem is you can't gap them correctly for a msd ignition. I took them out in favor of a ac plug, no problems since. Alan

 

Just watching the show you can tell it's all about selling stuff.
Looks like it works. The selling part anyways....

 

any new plug will likely perform better than a removed worn plug. platinum is a poor conductor which slows down metal transfer from ground to electrode. that's why they last so long. best real perfomance is from iron, copper or gold center electrodes. I have had much better results with Autolite and NGKs than any Bosch Platinum or other Iridium plugs.

 

Many years ago I replaced the AC plugs with Champion because "Champion plugs were racing plugs". The engine missed and stalled and I had to put the old ACs (back then you always keep spare parts in the trunk) back in on the New York Thruway. Used ACs ever since. The only way to know is to try them yourself.