I know about all the negative opinions of these plugs - but I am sold on them from years of use and very good results in completely different vehicles.

So unless you have actually installed them in your GXP or another Northstar application with bad results - please don't simply bash these plugs.

The part# that I came up with is B4458. Can anyone confirm this?

Anyone upgrade their spark plug wires while they were at it? I have a nice set of blue Taylor wires on my 30th Ann. TA. I have not looked yet at aftermarket wires for the GXP. But I will edit in with what I find. But let me know what you guys have found.

I have had the car for almost 3 weeks now and the windows are deep tinted, I have the K&N ready to install along with the Mobil 1 in 10-30W with a Mobil 1 oil filter too. I also have Xenon bulbs for the headlights - high and low beams - as well as the foglights. I will wait to install the foglight bulbs until after the wiring harness TSB work has been done though. Even picked up my license plates yesterday. I just need a nice license plate frame to pop the rear one in before I put it on as I won't be installing the front one. I just can't see defacing this beautiful vehicle with a front plate!

I will be searching for an aftermarket MAF like a Granetelli (since they are available for the Caddy'*), a smooth tube from the MAF to the Throttle Body, consider getting a ported Throttle Body as well as an electic cutout (QTP) in the future. I want to at least bump the car up to the 300HP mark and that should be no problem. Anything above that will be gravy as we really love our new GXP! Thanks in advance...

I'd be insterested in John'* opinions and research. I know he'* done quite a bit. Keeping in mind..he "used to" run nitrous on occasion.

I am wondering why you would change the platinum plugs that came stock. The LD8 was tuned as a high performance engine and comes with great plugs that are good for 90,000 miles and their life has been proven over and over again. Spark plugs cannot increase Hp. They either fire right or dont, but a colder range can help with predetonation. I am switching up to AC Delco Racing copper fine wire plugs with recessed tips '441LT' because of all the nitrous I gobble. They are 1 range colder than stock.

And Daytona.... I hate to break the news to ya, the LD8 does not use spark plug wires. You really need to take that pretty cover off and take a good look at your engine It has coil on plugs. I also like synthetic oil and switched up to Syntec at 1000 miles. A ported TB can only bring about 6 percent increase in power but if you feel the $250 is worth it, Morse Machine in Cali is well known for doing NorthstarTB'*.

The QTP is a good idea and have already checked it out and waiting for shop to have time to do it.... The Maf- good luck and would love to hear theres one available for the LD8 that works seemlessly with our PCM ( cant be flashed). A positive note for the stock Maf, it registers the extra flow from nitrous well and dont know if an aftermarket one is needed considering the limited mods that can be done to engine. The flexible air pipe from the Maf to the TB has the same diameter as the TB at its skinny segments so a smooth tube can bring only small gain and only if it is the same Diameter mentioned.

Not trying to bash your enthusiasm, I think it'* great. it'* just that the N* has so many performance issues normal to other GM engines covered, so we have to go beyond the obvious.

And Bill I never stopped injecting nitrous. The head bolt issue kind of got me skittish but I am not going to worry about it anymore. it it goes- it goes. As a matter of fact once the fine wire plugs are in, I am going back to the 125Hp shot for another try. I think if the new plugs keep me from the predetonation and the Maf can keep up with the flow, along with the QTP. I will be ready to hit the track for some reference.

Thanks Venom for the heads-up about the spark plug wires as I definitely wasn't aware of the coil-on-plug setup. That is terrific! And saves me a few extra bucks!

But hate to break the news to you - but HP can be made with spark plugs. There are some variables for sure - but there is definitely horsepower on the table. Lets minimize the variables and take a normally aspirated motor that will not see nitrous and choose a plug. You might still play with the heat range just to see the results - so say you try stock, one range colder, one range hotter. A lot of expense and effort and may or may not show a difference. You might then try copper VS platinum VS iridium. You might even try something like a Splitfire plug. But with all the aforementioned plugs - to get the absolute most out of them - you have to INDEX them. Which anyone who has done this - including myself - is a major pain in the rear to pick up just a handful of horsepower. BUT, with the Bosch Platinum +4'*, you get a great platinum plug with the benefit of 4 times the spark of a regular Bosch Platinum plug - and it doesn't even need to be indexed to give you maximum benefit. So it is really easy to see the benefit and the fact that yes - they will outperform the stock plugs. Dyno tests of these plugs have shown as much as a 1 HP per cylinder gain. Although I understand that to some that is not substantial - but to me it certainly is. I understand that every little bit counts and if I can pick up 4HP here and 6 HP there and a couple here and a couple there - that is a whole lot better than just running stock. And if it gets me another car length on the guy next to me at the stop light - it is way more than worth it.

So no problem regarding my enthusiasm as I was born with it when it comes to cars and I have always been a stickler for the details and if I can get just 1 more HP out of my car safely - then I want it! That has allowed me to win many a race over the years in a variety of vehicles against a variety of opponents - even when it was expected to go to the other guy. And it is not always about money - again, it is in the attention paid to the details and getting everything out of your setup safely.

And I don't down anyone for running nitrous no matter what the application - but it is not something I would personally ever run on one of my vehicles - but it definitely has it'* place. I joking tell people - "Bottles are for Babies"! - but it is just a joke. I just like knowing that the performance in my vehicle is there at all times and from all motor. You run guys on Nitrous and you win and so many times there is some excuse about how there bottle was empty - or they forgot to purge it - or the heater wasn't working - or 9 times out of 10 the pressure was too low! I tell ya - I've heard them all over the years.

I am the kinda guy who is going to tell you like it is and shoot straight. I won't tell you something doesn't work or does work unless I know for a fact myself that it does or doesn't. I try to stay open minded to the ideas of others and will always give credit to someone who builds a better mousetrap. But it seems that when someone does actually build a better mousetrap - it is always hard to find someone that is open-minded enough to even take the time to think through it and understand the concept so as to truly see that it is indeed a better mousetrap. And such is life...

But no problems and no worries as I am here to learn just as much as I am here to contribute. Thanks and talk to you later...

In some setups that 1Hp per cylinder exists I'm sure, especially plain ole flat bottoms found in most OEM engines. but I kinda doubt it can bring that much better performance than the tapered platinum tips that comes stock on our engines.

And as I said , I wasnt trying to slam ya..... a forum is about relating to other views. And though I'm well read and alot of years wrenching dont mean I know it all either. Probably not half of it.

You speak about 4 times the spark, but thats doesnt ring true to me If you put 16 tips on a plug you dont get 16 times the spark. just 16 times the ground and a plug only can only conduct as much current as the coil allows. If you increased the voltage and or amperage going through a plug then phrsics would allow this to be true as resistance is built.. Zex now sells a twin tipped plug with the tips at different points to help with predetonation (not for us yet ) but 4 tips seems futile for a stock engine with great plugs and no available way to up the current

They may help as you try to get 5-8 Hp here or there but thats relates to tenth'* of a sec.and not going to the car into the realm of what some imports are running at the track stock. But I am all for seeing somebody go thru all the little things to see how it all adds up, It'* just I want 2 seconds at least off published times and it cant be found that way.

Also when ya get the cover off you are in for the suprise of your life . the SSEi guys complain how hard the 3800'* are to get at back plugs and those engines are candy compared to ours..The big reason my fine wires arent on yet is i have to leave the car there at Dealers for a day. They say it'* not a get an appointment and wait type of thing. The EGR, Strut Crossmember and a few other things have to be taken off and it'* still a huge pain.

My nitrous is also a little different than your normal off the speed shop shelf variety. It has a computer of it'* own, variable flow gas valve thats responds to the bottle pressure and the orifaces chosen for the jets. And activates by TPS voltage which is determined by me as I go thru the computers learn procedure. ....If the new plugs and exhaust cutout kill the predetonation and the Maf registers ok, I will be moving up to a fog setup with minature combo jets tapped into top of manifold in each intake tube . The jets are fed by 8 way manifolds for both nitrous and gas lines. Also an inline high pressure fuel pump that is also TPS activated willl be installed. I love the look of the fog setup and will make the car even better at shows.

Nice to meet a N* owner that has opinions and writes in more than one paragraph I looooove to BS about our engines.

Cool! I 'aint't skeert' of no spark plugs after doing the ones on my 30th Ann. TA! I spent 3 hours on just the 8th plug by itself! So these probably won't be fun - but they shouldn't be too bad either. And pulling the STB on this car will be easier than pulling the one on my TA too.

As far as those tenths of a second - that is all I am looking for in the GXP. My go quick / go fast car is my TA. Oh, and you still ought to take a good look at those Platinum +4'* though just to grasp what I am talking about. Talk to you later...

Go get em !and take pics if you can, You might be the first GXP to do this. And I'm real interested in just how diffucult they are. Whether they do some measurable gain or not, I really need to quiet my detonation and possibly run a little cooler so the recessed fine wire plugs seem like the ticket for my application.

I seen the poster at Advance for them and did take a good look at that. And wondered about them since I seen it. I was born a doubting Thomas so dont let it get ya. Just because I'm skepticle doesnt mean i'm not interested.

The +4 plugs have 4 electrodes, but the current will take the path of least resistance. This means that 3 electrodes are just sitting there. The concept looks good on paper but in reality does not work out. This how I see it, if someone can correct me I stand corrected.

That was my feeling but I have seen videos, since I first commented, of multible electrodes firing simutanously and back and forth, We've beat the theory here to death. I interested in hearing how the new plugs run. I am stubborn about switching views but open minded enuff to accept what I see. I often wish I had a dyno near and cheap like Rogue to see what these little things can actually do for a motor.