[Formulajones]

I was just at Napa yesterday and enquired about the NGK part numbers.

They do still carry the BKR5E plug and had them in stock. The confusion started because Napa uses part number 7938 for that plug. Their part number doesn't have anything that resembles the "5" heat range. So I had him bring them out for a look.

They are in fact a V-power plug, 5/8", with 3/4" reach and gasketed, and extended reach electrode. So they are for the typical aluminum head applications. And they had the BKR5E part number stamped in them.

I compared them to some 3924 Autolites they also had in stock and they are the same design, thread, length, gasket etc...

Not sure why they have them listed under a different part number. Oddly I checked Autozone and they are doing the same thing. They also had them in stock.

[Scott65]

The other number is what they call a stock number and I guess they take that literally. The NGK site, one of the pages anyway, lists them by both. That helps when you have both numbers with talking to parts people. Navigating the subject, and the websites of spark plugs isn't as easy as it oughta be...
ETA: one of my previous post in this thread has the correct STOCK number for the BKR6E, 6962 I believe.
Double checked and that is the correct stock number for anyone interested in the BKR6E, which is the correct style/design plug for Edelbrocks, with a projected tip in a 6 heat range. Which is ~1 heat range colder than the plug recommendation in the Edelbrock recommendation in the new package literature (at least at the time I purchased them ~12 years) Best I can tell the BKR5E or 7938 is the cross for the recommended 3924 Autolite or Champion 12 heat range, again at that time.
The newer heads with the newer combustion chamber design, I don't know their recommendation. But the cross numbers and heat ranges remain the same depending on which is recommended.
Hopefully this ends up narrowing confusion for someone.

[Formulajones]

I would guess the recommendation for the newer design chamber on the Pontiacs would be the same, because the AFR's that I run on a BBC with a modern chamber recommends the exact same plug.


The bad part about the stock number is just what you said, the auto parts stores are taking that literally and don't have the typical plug numbers on the computer that you and I look for. Makes me wonder if some counter guys might look at that and tell you they don't have them in stock or are discontinued. Luckily I deal with a good guy at Napa that knew what was going on.

[Scott65]

Maybe if a few of us were willing, and if there's enough interest, we could get a sticky made to help lessen the confusion.

[Formulajones]

I'm more than willing to help do what ever I can if needed.

[Scott65]

Me too, shouldn't take much. I'm not as familiar with the race plugs for Pontiacs. We used them years ago on BBC Super Gas car. I believe the heat ranges get colder with bigger numbers on those too, and most don't have projected tips. Some are non resistor too. Guess it depends on how involved it needs to be. For the street section maybe just a straight cross to Autolite/Champion recommended starting point, and the corresponding changes to go colder? Not sure if hotter would ever be necessary? And all this on a new concise single post. Hopefully Bart would sticky it for us.

[Formulajones]

Something odd with the NGK site. I was trying to find the stock number for BKR6E (the standard copper plug) and the only stock number they cross that over to is the BKR6IX which is their Iridium plug.

When I check their site for the BKR5E that I already know is stock number 7938
It too comes back with the iridium plug with a stock number 6341

If you know of another page that actually displays all the stock numbers please let me know. I'm beginning to think the plug dad has been running isn't a resistor plug. The "R" in the part number at the beginning I believe stands for their racing plug, even though that part number he is running does not come up on their site at all. Plus it's not a projected tip which bugs the hell outta me He really should have resistor plugs in there with the EFI.

[Scott65]

I'll start:
This is intended to be a help to those looking to cross reference from the starting recommendations of Edelbrock in reference to spark plugs for your Edelbrock headed(and others using this design/style of plug) to NGK. Whatever your reason, loss of confidence in current brand, or just experimentation, the part numbers can cause confusion and perhaps discouragement from making the change.
We'll start with the numbers of the Autolite and Champions, then go colder from there.

Autolite 3924 Champion RC12YC NGK BKR5E Stock# 7938(heat range 5)
Autolite 3923 Champion RC9YC NGK BKR6E Stock# 6962(heat range 6)
Autolite 3922 Champion xxxxx NGK BKR7E Stock# 4644(heat range 7)

This can be "it' or a starting point.
I did reverse check all the NGK numbers. i.e. I looked them up by both numbers to make sure the same plug came up.
If someone wants to do the race version plugs, great. I'm not sure whether keeping it simple for the street section is sufficient or more is wanted.
If this becomes longer or more involved, then maybe a word document shared via email between those contributing would be easier. Or perhaps a download of the word document, or maybe xcell spreadsheet, as formatting this type post sucks... Maybe it's just my computer skills...Then a final, single post for the sticky if approved?

[Scott65]

FJ, I could not find a Racing version that was resistor when I was looking. Due to my ecu/electronics, a non resistor is out of the question for me

[Formulajones]

Originally Posted by Scott65

FJ, I could not find a Racing version that was resistor when I was looking. Due to my ecu/electronics, a non resistor is out of the question for me

That's what I'm finding too. Oddly his EFI has been working fine with no wonky symptoms but he really should have a resistor plug in it.

[Formulajones]

Not to confuse things but I'll add the big plug for the iron head guys (pre 1971)

Short plug with gasket 13/16 extended tip. This would replace the AC R43S number or 44-45 heat ranges.

The NKG is oddly only now listing 2 heat ranges in this plug and if you try to search for it on their site they give you an XR5DC part number.

The XR4's and 5's are available at my local parts stores. Don't know what the DC is.

XR4 stock #5858

XR5 stock #3332

The Autolite equivilents would be Autolite 85, 86 or 87.

[Scott65]

Originally Posted by Formulajones

That's what I'm finding too. Oddly his EFI has been working fine with no wonky symptoms but he really should have a resistor plug in it.

"Maybe" the resistor plug wires are doing enough? I'm not gonna chance it on mine. I have crank and cam sensor wires to deal with. Y'all probably pick all that up from a dual sync distributor huh?

[Scott65]

Looking at my post on the plug cross reference, it's too garbled in this format. I will ATTEMPT an excel spreadsheet, and see if the size limitations will allow it to be an upload able attachment. Later, got stuff to do now. Gonna attempt to get my android dashboard working... Change the oil in the truck, yardwork... Tonight maybe.

[Scott65]

Maybe someone can tackle the tapered seat version crossed to the common AC's R45, 4, and 3 TS?
Also if anyone could confirm the other Aluminum heads which use the Autolite 392x style plug it could be notated. But I've only used the Edelbrocks.
ETA: If you have information on any of the other Aluminum heads, include their recommendation of plug number and brand just in case there are any drastic differences, even though that wouldn't affect crossover numbers.

[Formulajones]

I can tackle that, I use them.

The 3/4" reach spark plugs are used throughout many of the aluminum heads. The Trick Flows for Ford and Chevy, the AFR's I use on BBC and SBC, and pretty sure the Kauffman Pontiac heads also use 3/4" reach plugs. So those plugs will work among many brand engines that are running aftermarket aluminum heads.

Shucks they even work on air cooled VW's with aftermarket aluminum heads, they use 3/4" reach too. (yeah we are into air cooled VW's too)

I'll get the small 5/8 plug taper seat stuff I use here shortly. On the AC number you posted, that would be correct. R45TS for example. T is for the taper seat and S is for the extended tip.

Edit: Went out and looked at my stash. Autolites would be 25, 26, 27 and the NGK's are UR5, or 4 or 6, what ever heat range you want.

[Scott65]

Cool, I'll work on an excel spreadsheet (in caveman fashion) tonight. Got my dash mostly set up. See my sequential fuel spark thread for anyone interested.

[Formulajones]

Taper seat 5/8 plug with extended tip. For 71 and later stock cylinder heads.


UR4 is stock #6630 Autolite equivalent is 25
UR5 is stock #2771 Autolite equivalent is 24
UR6 is stock #7773 Autolite equivalent is 23

These are the replacements for AC Delco R43TS, R44TS, and R45TS


Pretty sure those are the heat ranges crossed over as well, correct me if I'm off on that Scott.

[jeff chmura]

Will this link help???
https://www.angelfire.com/extreme4/s..._REFERENCE.htm

[Scott65]

It is in a way. There are some mistakes, like plugs that say they'll match the Champions, but have a 13/16" head that won't clear the counterbores on the E heads.And it's terrible to try to read for my old eyes. I will research this further, and pare it down to known good cross matches. For our Pontiacs. That list is comprehensive, and needlessly busy for the Pontiac enthusiast that doesn't need all that.

[Formulajones]

If you look at it long enough you'll find a few things I've complained about when it comes to AC Delco plugs, like their lack of heat ranges anymore. Especially when it comes to 3/4" reach plugs. The only one they list, (and I've run them in the past) are the FR1LS plugs. That's the only one they offer. If you really want to play with heat ranges you're forced to jump into one of the other brands. In the end it's what pushed me to drop AC all together as it became harder to find what I wanted.

That list also does what many others do, and that's substitute the same heat range in one plug to cover 2 or 3 other heat ranges in another plug, again for lack of choices in a particular brand. Makes comparing heat ranges a bit difficult.

Not knocking the list, thanks for putting it up Jeff, just pointing out why spark plugs can be such a confusing subject for many.