I've had the best luck on my current combo with NGK's, change them once a year!

 

Bob are you using 5's or 6's ?
BRK5E11?

 

i have used many different plugs for different aplications..had a 350 with just under 12:1 and it liked hot plugs better than the colder ones,,i ran a champion Rj12yc in that one..they reved the most and lasted longest. the autolights in the replacement were the worst of the bunch,,

But in other aplications the autolights were fine.
Whatever plug i use in my performance stuff i like to cut the ground strap back..i will try to load a pic..this is a standard ACR45ts
As for yours start a step above the coldest and work your way up..I have never liked the coldest plug of the bunch..your results may varry.

You can cut the strap back all the way to the edge if you like..some i have done that way..I think this exposes the flame kernel a tad more..

Any power gain you ask? ..Dont know but i sleep better knowing it aint stock This plug is old and in the scrap bin. many 10,000's of miles and cleaned with a wire wheel

 

http://www.championsparkplugs.com/sparkplug411_manufacturer.asp?manufacturerID=2

This is what Champion calls the "J" gap. A popular plug with point ignitions had the designation "UJ" which was a cut back side electrode with an extra gap, about .020", inside the insulator to raise firing voltage. They worked quite well. Years ago, the Champion rep hung around the bike shop, but I haven't seen him in years.

 

I use Accel header plugs in my '71. The '70 gets AC Delco plugs. I would be running Delco's in the '71, but they are too long for the small block with headers.

 

I've had good luck with NGK's. I run a -7 heat range racing plug which is perfect for my street combo.

 

I have also had good luck with NGK's on my engine.:yes:

 

Was running Autolite AR3924. Then tried AP3923 Platinum tip with the prior motor. Swapped back to the AR3924 for the 540" install which is what Dart specs for a street plug.

 

Except for 1 season when I used the Champions that Brodix recommended,my big block has always had AC Delco's,and they usually get changed every year,although this set is on their second season and still look pretty good.
Guy

 

Ngk yr5

 

I used Champion plugs, almost exclusively, for many years but their quality seemed to go downhill a few years ago. Am now using Autolite plugs with excellent results. As far as heat range goes, the best place to start is the recommended range for your particular engine. If compression is higher than stock, then go one or two steps colder. If the engine is burning oil at all and the plugs are fouling, then go one or two steps hotter.
Use an illuminated plug inspection tool to accurately determine spark plug condition.

 

i'm running ac delco r44lts, not sure if this is a good plug or not.

engine guy, where do you buy the illumination tool? i'm trying to learn how to read plugs. i have a 10x magnifier and i can't see the base of the porcelin. from what i've read you can look there for mixture or the base ring. so i've just been looking at the base ring.

 

I use R5671A-7 in my 460 with Brodix RR-O heads at 10.5:1. They recommend a -8 plug for an engine using race fuel and -7 for pump gas. -8 was too cold for my combo and I believe it was the BKR6E that I tried and they were too hot. The -7 racing plug is just right.

 

You really need to determine this through some experimenting. You have a lot of compression but there is also fuel system and timing that play a huge role. For 12 to 1 motor don't go cheap, you can cause a lot of damage if you don't pay attention to what's going on with the motor.

You can use A/F ratio readings for rich/lean but you also need to check the plugs for heat range and timing. I'm not an expert at reading plugs but someone who I think is told me to look at the plug threads for heat range and the electrode strap for timing, just a couple of indicators...JMO...

 

14 to 1 565
Engine only NGK -8
up to 300 Nitrous -9
300-600 Nitrous -10

 

14 to 1 565
Engine only NGK -8
up to 300 Nitrous -9
300-600 Nitrous -10

That has to be one heck of an adrenaline rush! :thumbsup:

 

R5671A-7 ngk

 

R5671A-8 ngk. NGK is one of the best for reading. They are plated and change color quickly. Davey is correct about the ground strap and the threads/flat at the end of the threads. At least that is what I was told and have read.

 

Same plug I'm running.

 

As much as I hate to say it being a diehard Chevy guy, I've always used Autolite AR series plugs in my hot rods They are easy to read and the ground strap is cut back, too. FWIW...

 

As much as I hate to say it being a diehard Chevy guy, I've always used Autolite AR series plugs in my hot rods They are easy to read and the ground strap is cut back, too. FWIW...

that's what I'm using...AR3932's right now....

 

I have been trying to run AC 41-629 (new number for FR3LS)

I have had at least 5 of them that were bad right out of the box or went bad within short order and still looked like new.

Had a miss last weekend at the track, changed out to a new set, miss got even worse to the point I couldn't stay into it the whole way down. Changed wires, cap, carb, coil, everything to try and find it, and again it was one of this new set of plugs I installed. Put in some Champions as a last ditch effort, and ran like a top.

I will NEVER run one of these AC plugs again. I noticed they are Hecho en Mexico, must not have good QC on them down there....

Just a tip.

 

yes I use the ground strap for timing too. I'm memory challenged myself so I just believe everything I read on the internet...

 

8

 

I have tried the R5671A-7 the plug I was using when I blew the head gasket this spring. So I moved to the -9 with the Alky. When I converted back to the E85 I tried the -8 and it looked just a little too lean to me but I am no expert at reading plugs so I put the -9's back on to be safe. That is what I have been running lately but they look just like they are a little too dark after a run. Hmmm...Eric68 said he likes the AR3933 for our compression on E85 so I bought a set today and set the gap at .028. Hopefully, this plug will be right. Like Davey said they go in half step increments.

 

Even though Autolite was originally a spin-off of Motorcraft

I think you have that backwards--Autolite began in 1911; Motorcraft was started in 1972 by Ford.

 

Thanks Mike, I stand corrected. Autolite was/is a major supplier to Ford, going back to the earliest models that Ford produced. Same situation with Holley. Holley was a supplier to Ford for many years and at one time about the only cars that were produced with Holley carburetors were Fords. Many of us considered Holleys to be "Ford" carburetors until the mid 60's. Holleys were used by other brands however, such as International Harvester, American Motors, etc. Sorry, got off the topic again.

 

thanks guys...

 

NGK's Pro-Filer 210 heads

 

When I ran nitrous more often I had good luck with Autolite race plugs, but being a cheap bastard I switched to NGK's which are half as much money. The Autolites seemed to last a little longer, but the cost difference outweighed the life difference. I run R5671A-9 (10's w/bottle)
Never have any issues with them, even puttering in traffic.

 

Couple follow up questions.

My engine builder recommended R5671A-9s and I ended up fouling those out so was researching the forum and talking to other BBC guys. I definitely am going to a hotter plug but I also noticed the standard recommendations for BBCs call for a tapered (peanut) plug and a smaller reach (.460 versus 3/4). I have now ran both reaches and suprised the 3/4 fit and ran somewhat well until they fouled out with low rpm cruising in cold weather. What impact does the additional reach have, if any?

Also, looking at new NGKs -7s tapered plugs and debating on projected versus non-projected. Appears the Autolites mentioned in this post are projected and the NGK are non-projected. What is the difference with the differnt insulator type? So many choices.

Specs:

454 LS6 12.5:1 running racing gas in very humid weather in Chicago

David

 

NGK FR5 Stock # 7373 454 Isky 288 worked O-Port heads. Good Street plug.

 

NGK -7. 10.3 cr as has been said easy to read....... I look at ground strap for heat range check