Spark Plug recommendation; blown 360

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Bill Dedman

Bill Dedman

bill dedman
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Location
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I am finally about to get the blower (Vortech blow-thru carb setup) working on my 360 Magnum.

I have read that extended tip plugs are not the way to go with a forced induction engine, and am in need of some advice from anyone who's run a blower on a small block Mopar, Magnum or not.

I wonder if there's any truth to that rumor about the extended tip plugs, and what plugs might run well in a mildly-supercharged 360 Magnum on the street.

It will have 7-9 pounds of boost and a 6-grand redline, and make 420-450 HP, in all likelihood. Compression ratio is a true 9:1.

Any info will be much appreciated.

Bill, in Conway, Arkansas
 
Bob, Thanks a lot for the reply.

I have heard that you don't want to put an extended tip plug in an engine that's going to see boost, because the extended ground-electrode will turn cherry red and act like a glow-plug under periods of boost longer than a few econds. I don't have any idea if that's true, but this NGK plug you recommended looks like an extended tip plug in the pictures, to me.

Have you used this particular type of plug in a blown engine, and will it screw into a Magnum head? I'm not sure if the Magnum heads take the same plug as L-A heads, size-wise and thread-kength-wise.

Thats much for any information!!!
 
I don't know what kind of heads you are running; Magnum or not... If they're not Magnum heads, they may have a different thread and might not fit; that was one concern.

Is your engine supercharged? I assume it is, but have no information about it. If it's anywhere near what I have, I'm sure they'd work for me, too.
Send me an email at [email protected] and I'll email you my address.

I don't have a PM account.

Thanks VERY MUCH for the info; I appreciate it a lot. I'm about to get this thing running with the blower for the first time, and I don't want to screw it up with the wrong plug.... I've waited a long time for this.

What is your motor setup, Bob?

Bill, in Conway, AR
 
Kern,
Thanks a lot for the info and photos. That's a real sanitary installation. Can you tell me a little about how it runs, and your cam specs?

I have no idea as to how this engine of mine is going to react to this blower. It's a Vortech "V-1." S-trim. I have pulleys sized to gine 50-K impeller rpm (design-spec maximum recommended speed) at 6,00 crankshaft rpm, my redline.

The engine is a VERY mildly modified 360 Magnum with pocket-ported (only) heads, a 3-angle valve job, 9:1 (true) compression, and a 214/218 degree at .050"-lift hydraulic roller cam, (114 degree lobe separation) using a 750 D.P. Holley carb modified by the Carb Shop for blow-thru. It has a 904 tranny with a shift kit and a 2,500-rpm-stall converter hooked to a 3.55 Auburn Limited Slip 8.75" rear.

I am looking for plug recommendations, as I don't have a clue (beyond the good advice from Bob) as to what might work well.

On a 95-degree day, my car ran low 13's normally-aspirated, with 340 exhaust manifolds and an M-P water-heated intake manifold with a 750 Holley on top.

Now, it has TTI step-headers, a "Chinese Air-Gap" and an 850 double pumper, along with the blower.

The car weighs 3,340 without me in it... 60-foots are 1.91 usually, on 8"-wide drag radials.

I am trying to pick up a second on e.t., (low 12's) and I realize that's a lot....
Can I do this??? Did your car pick up a second with the blower?

How much boost do you think I might get (and, how much do you run???)

Thanks for any ideas, information, or suggestions!!!

Bill, in Conway, Arkansas
 
Nope, I haven't tried ANY spark plug yet. I can't get an answer from anyone on the question I asked about extended-tip plugs and the problems they supposedly have under boost.

I hate to buy anythng 'til I've got some good info about that. Then, I'll certainly consider irridium, for sure.

Thanks for the comment!
 
Thanks for the correction, Bob! Yhat other number was for a lawnmower plug... LOL!

I STILL don't know if that plug will screw into a Magnum head, though. Do you have any idea about that?
 
Bill Dedman said:
Thanks for the correction, Bob! Yhat other number was for a lawnmower plug... LOL!

I STILL don't know if that plug will screw into a Magnum head, though. Do you have any idea about that?
Click to expand...
I’m in the same boat you were
I got a warmed over 360magnum with a 100 shot of gas it was recommended
To me to use bkr6e or bkr7e NGK
And when I put the ngk plug next to the factory recommended plug for a stock engine the tip projection on the bkr6e was half of the factory recommended plug Sure would be interested in what you find out
 
The correct spark plug for SBM Forced Induction is :

NGK 5671-9

But you might be able to get away with a
NGK BR8ES
 
Prine said:
The correct spark plug for SBM Forced Induction is :

NGK 5671-9

But you might be able to get away with a
NGK BR8ES
Click to expand...

Unfortunately, Bill Dedman is no longer with us. Do you see the "Legendary Member" status under his screen name? That means a member has passed away. He was a good old dude, too. He had just roughly finished a really cool 64 turbo Valiant build, too.
 
Wow,...I knew him., and didnt know he passed....my sympathies.
AND I'm 13 years late.....( 2007 !!)
 
Prine said:
Wow,...I knew him., and didnt know he passed....my sympathies.
AND I'm 13 years late.....( 2007 !!)
Click to expand...

Yup. He had a debilitating stroke and was in a nursing home for a while before he passed.
 
Prine said:
The correct spark plug for SBM Forced Induction is :

NGK 5671-9

But you might be able to get away with a
NGK BR8ES
Click to expand...
According to another member mopar issued a technical service bulletin on the 360 magnum to use ngk bkr6es to reduce detonation. I also spoke to ngk and they said that the ngk bkr6es as a starting point. However I will start with bkr7es (one step colder)being the
safety pup that I am
If plugs for nitrous are different than forced induction then I’m sorry to have opened my big mouth
 
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Brooks James said:
According to another member mopar issued a technical service bulletin on the 360 magnum to use ngk bkr6es to reduce detonation. I also spoke to ngk and they said that the ngk bkr6es as a starting point. However I will start with bkr7es (one step colder)being the
safety pup that I am
If plugs for nitrous are different than forced induction then I’m sorry to have opened my big mouth
Click to expand...
 
Brooks, the spark plugs you listed have a “projected tip” ...
The spark plugs Prine suggested to use have a “non projected tip”...

Typically with boost or nitrous one would use a one step colder, non projected tip spark plug with a slightly tighter gap.
 
Last edited:
MiradaMegaCab said:
Brooks, the spark plugs you listed have a “projected tip” ...
The spark plugs Prine suggested to use have a “non projected tip”...


Typically with boost or nitrous one would use a one step colder, non projected tip spark plug with a slightly tighter gap.
Click to expand...

I give up I’ve gotten 6 different opinions two different ones from ngk alone
 
Don't try to over think it. When all else fails, keep it simple. Start with the stock plug for the given engine and work from there. That way, you'll have a real base line.
 
RustyRatRod said:
Don't try to over think it. When all else fails, keep it simple. Start with the stock plug for the given engine and work from there. That way, you'll have a real base line.
Click to expand...
Thank you that’s the best advice I’ve gotten to date
 
The bkr6e and bkr7e have been used by many guys in the dakota rt world with great success on power adder applications. As prine suggested if you want a non projected tip plug use the br6es or br7es.
 
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