What size NGK plugs should i try?

[wally426ci]

Its about time i start working on my car instead of just driving it. After getting it running right, i just cant stop. But i need to get on a few things. I was gonna try out some other plugs for my 408 stroker.... Im running Champion RN12YC i think its RN.....

[71chally416]

That would be BPR5ES for resistor plugs.

You should be flogged for using Champion plugs 

[Chryco Psycho]

My bet is if you can tell the difference at all it will be worse

[Aussie Challenger]

That would be BPR5ES for resistor plugs.

You should be flogged for using Champion plugs 

  I would use BPR5EY for cruising and BPR6EY highway and traffic light derby's.
  The "Y" means that the electrode has a "V" groove and it gives a better spark and are the same price as the "S" plugs. I only use NGK now days because they are so reliable and no come backs.      

[Mike70]

Way back when, Champion was all I ever put in my Challenger. Chryco, are you saying that the NGK will be worse? So you like Champion also?

[Chryco Psycho]

Yeah I use Champion , , I have always had fouling problems with NGK but only if the mixture is off or the choke fouls the plug then they quit firing.
 a few years ago we did a dyno test with all the major brands of spark plugs looking for every last HP in a race engine & it was proven that the cheapest plugs made the most power & the more the plug cost the less power it made

[wally426ci]

  Interesting..... I had always heard good about NGK... ah, maybe i'll pull em and see what they look like.... 

[71chally416]

Here's an interesting sparkplug dyno test they did on stock SRT-4. Being that it's only a 4 banger you can probably expect twice the gain on a V8. Best numbers are indicated in red.
http://www.srtforums.com/forums/f308/srt4-sparkplug-shootout-dyno-results-409262/

[wally426ci]

[74 340 4speed]

I've run Champion, Autolite and NGK in my 340.  The champions would foul out in 3 trips around the block.  The autolites lasted about 5 trips. I put the NGK's in almost a year ago now and haven't had any problems since.  I think I have BPR6ES if I'm not mistaken.  I crossed the champion # that I originally run to the autolite plug first, then crossed that to the ngk plug.  To my knowledge, I didn't change the heat range.  I went by what the books told me.

[Moparal]

I run autolite 85's in my 440-6. They have been in there since new. I run a point ignition system. Runs good cold or hot. I havent had an issue. I run stock ignition wires with it also.