i have read in higher boost gen 5 engines ngk have problems , brisk doing good and i think all people change to them for boosted application .

RR14YS are the plugs in my truck. Brisk shows 15 as stock. Heat range is a variable dependent on different manufactures. All I know is we were able to pack more advance in this engine than I thought we could at 5lbs of boost. 491lbft of torque and 436hp on 5 psi with 93 octane. I drive it everyday like I stole it. So far so good. About 4000 miles on the plugs and just about 2000 on the turbo.

How much more timing? how much are you now WOT?

It held 20* on 93 and on back to back pulls it only varied by 1hp. It swings from 16-20 from 3500-5800rpm. We started at a max of 12* and kept bumping it based on improvement and no knock. It showed improvement with each bump so we continued to add it 2* at a time. We stopped at 20 and never really found the knock threshold. Mind you it’s only 5 psi but that’s still a fair amount of advance. I know most stock L83s are at the 20* mark from the factory so that surprised me a little bit.

ya 5 lbs @ 20* Seems real good,your goal to up the boost any time soon? If you could get 2* more advance with the brisk plugs over a maggy or whipple recommended plug that would be impressive.

I am running what whipple sent gapped at .030
8 New NGK IRIDIUM IX Spark Plug LZTR7AIX-13

My plugs are gapped at .040. For now and seem to work just fine. I made a slight mistake when I had it tuned, I thought the wastegate spring was an 8lb spring but the data showed it to only hold 5.5. I originally thought I had exhaust or charge tube leaks but after testing everything with a smoke machine at 4psi I could not find a leak that would be causing that much pressure loss. I had 1-2 small leaks but after correcting them I still stopped the map at 137kpa. I did conduct 1 test run to confirm it would hold more and it easily shot to 170kpa and I couldn’t let off fast enough. Advance was locked at 10* and never showed knock so I left it alone and kept it at 5psi. I would like to max the stock fuel system but haven’t hand the time to play with it lately. I drive it everyday so bottom line is it needs to function. I’m not afraid of cranking it to the moon but why break more parts than I need to while driving back and forth to work.

Just thinking about i did do some testing in regards to the amount of ignition lead relative to the plugs. Basic setup was stock L83 with LT1 intake manifold and throttle body and no muffler. It did allow for more consistent 81mph traps in the 1/8. Problem with my data being conclusive is I was playing with tire pressure at the same time. I need to revisit my log data but I know I could put 30-31* advance on E85 with the brisk plugs. I try not to focus on how much lead I can cram in but rather how much I gain from each increase. If it stops gaining power there is no need to increase cylinder pressure. It just wears parts out faster. Prior to this test session I was running 28-29* and increasing never showed good improvement and trapped 80-80.5. So what exactly caused the increased trap speed is a variable I have zero conclusive proof to illustrate you can increase ignition lead. I did however use my plex knock monitor before and after changing the plugs and from what I was able to see it did effect tip in combustion frequency which was the only reason I tried the plugs to begin with. I ran the audio output back through some simple audio editing software and it definatley showed me that the plugs changed what I believe to be how the flame front started. It was much more even in frequency without huge spikes that are clear indicators of knock. Please keep in mind that variables still exist with this scinaro as well.

My Whipple also came with these plugs, which I'm using as well.
(NGK IRIDIUM IX Spark Plug LZTR7AIX-13)