Cold plugs for 360 Magnum

Can anyone recommend a good cold plug for a 2,000-model-year Durango, 5.9-liter (360) Mopar Magnum motor? I bought some cold NGK's and when I went to install them, I discovered that they had a 13/16ths-inch hex, and wouldn't fit in the spark plug wells in the heads.

I need plugs with no extended tip, a very cold range, and a 5/8ths-inch hex. I THINK the "reach" is 3/4ths-inch. Not positive about that.... sorry.

I got my car running well, finally (ended up having to replace the distributor before it would run right,) but I still need some "cold" spark plugs for it. It still seems to want to detonate a little, with these "6962" NGK plugs that are also marked "BKR6E". I'm hoping that some colder plugs might cure the detonation.

I have an MSD BoostMaster ignition-retard set on 3-degrees of retard for every pound of boost (30 degrees advance, total, with no retard), and 375ml-jet in my Snowperformance Stage I BoostCooler with windshield-washer fluid; spraying begins at 5 psi. I STILL hear some trace detonation at full throttle; can't live with that.

I run 8 pounds of boost.... so far.

Any recommendations for a cold plug (preferably, NGK's, but not exclusively.)

Thanks for any information or recommendations.

Bill, in Conway, Arkansas

Something just does not seem right. I installed a S-Trim on a Durango 5.9 making 6psi with stock timing and no retard unit. The only thing we installed was a ignition box. The person uses 91 octane and he never had detonation even in 95 degree days. I had that truck on the dyno many times and the wideband was perfect. It is hard for me to except that your removing that much timing and using water injection and getting detonation. Are you running that Carb that lean on the jets?

I am running a pretty small pulley on top (2.87") and am making 8 pounds of boost, but this this thing starts detonating (or, it SOUNDS like detonation to me... a metallic "ping" at random intervals) almost as soon as it starts making ANY boost at all.

The new Holley 4150 750-dp carb was delivered to me from The Carb Shop in Ontario, CA with an operational "65" power valve, .72 main jets and .32adjustable air bleeds, with .46 pump squirters. I have richened it up with .78 main jets, .26 adjustable air bleeds and .72 squirters.

It has a brand new M-P distributor that is MILDLY curved.

This thing is not lean.... The float levels are correct and I have checked for a vacuum leak.

Shouldn't be detonating... but, I think it is.

Thanks for your attempt to analyze what's going on. I am mystified.

I just really need to know what kind of plugs to put in it.

Any ideas?

Just out of curiosity; I only this week got this thing running with the blower.

I have not had time to do a chassis dyno pull or get it to the drag strip.

It has the following mods... 360 Magnum: Vortech V-1, S-Trim, 8 psi boost; TTI stepped headers; Hughes cam (hyd. roller, .525" lift with 214/218 duration @ .050"; 114-degree lobe separation; Air Gap intake manifold, stock Magnum heads (bowl ported only), true 9:1 compression; 750 Holley dbl. pmpr.; 3,300 pounds w/o driver; 3.55 Sure Grip 8.75" rear; B.F. Goodrich T/A 8"-wide drag radials, 26" tall; spring clams. air bag and pinion snubber in the rear; 90-10 shocks in the front.

Since you ran that other 360 on the dyno, I was just curious as to what kind of power it made. I'm hoping for about 425 at the rear wheels.

Is that reasonable? It ran 13.35 unblown, at sea-level on a 95 degree day...

Thanks for any information.

Jeg's has a really good website with regard to NGK plugs, and I was able to find just what I needed on their site.

NGK R5671A-11

Some friends of mine and I have rented the local strip for Sunday, Feb. 15 from noon 'til 4 p.m. If we can get some decent weather for that weekend, maybe I will FINALLY have some performance numbers to report.

It's been a long time coming!!! Wish me luck.

What is your weather like?
I have 10" of snow listed for today and 15 degrees.
I just want to hear about some weather that is better than mine.
Thanks

Speedytang,

I live in Central Arkansas, about 25 miles NorthWest of Little Rock.

Yesterday, about 1 p.m., the temperature dropped to just below freezing, and it started raining.... turning to ice almost as soon as it hit the ground. That went on for HOURS... slicked the roads up REAL good, and it took me about five minutes to get the door open on my car... frozen shut SOLID, with ice...

Last night, it was cold, but quit raining. I just got up at noon, today, and it's 33 degrees, but the forecast is for more freezing rain Tuesday, and snow on Wednesday, so we're not going to have any decent weather for a while...

Does that make you feel any better??? :) Misery loves company, I know. lol!

We have the drag strip rented on Feb. 15th for testing... it had better warm up before then!!! I want to get a time slip on this slug sitting in my driveway; been waiting FOREVER to get one... Hoping for 1-sec improvement with the addition of this V-1, S-trim Vortech, some stepped headers and an Air-Gap style (Crosswind) intake manifold. 8 pounds of boost, max.

Think all that might be worth a second? I sure hope so... it was running about 13-flat quarter mile times, before. Oh; almost forgot... I picked up a 4.10:1, limited-slip center section (running a 3.55 SureGrip, now), but I might not get that installed before the 15th. The 4.10 might be worth .2????

I am determined to get this piece of junk into the 11's.... somehow, some way! 3,550-pounds of road-hugging weight, with driver aboard...

Wish me luck!

Stay warm!!!

Speedytang, and others who might be interested...

I finally got a chance to run my car on a reliable set of clocks over the weekend.
Centervile (Arkansas) Dragway allowed 5 of us to rent the strip on Sunday from 11 to 5 pm, and we had ample opportunity to make as many passes as we deemed appropriate.

This is a thousand-foot strip; not enough shutdown area for a full quarter-mile. They gave us timelips with 60-ft, 330-ft, 660-ft and 1,000-ft incremental times, with mph at 660 and 1,000-ft.

Attached is a copy of my best timeslip.

I was running 10 pounds of boost.

It was very cold, and the starting line was really slick, so my 60-foot time shown is not representative of what the car can do on a good-biting strip.

Still, I was more than happy with the results. With changing intake and exhaust manifolds and adding the V-1, S-trim blower, I picked up over 13 mph in the thousand feet, and dropped the 1,000 ft e.t. from 11.0 to 9.74, a total of 1.26 seconds.

My online computer programs say the car, given the numbers on the time slip, should run about 11.80 @ 118 mph in the quarter.

That's an improvement of 1.55 seconds and 16 mph, compared with my unblown best times of 13.35 @ 102 mph.

This was a long time, coming.... and was even more gratifying since there was no "kit" and I had to fabricate the mounting plate, oil supply line and drainback, and all the hot air plumbing, myself. I also built a dual-fuel system with two pumps, and two filters, whether the fuel comes from the original tank, or the fuel cell in the trunk. That's a half-inch system, all the way.

Okay; I'll stop the bragging, now.... LOL! If you knew how ham-handed I am, you'd realize what a miracle it is that this thing runs at all.... I still haven't put a timing light on it.... just tuned it "by ear."

I was just happy that the head gaskets stayed put during all 6 runs. I have a bigger top pulley that I'm going to install, tomorrow, and cut the boost down to about 8 pounds. I was running a 2.87"; the larger one is a 3.04"...

The MSD BoostMaster and my SnowPerformance Boost Cooler seemed to work flawlessly throughout. Had the MSD set on "3" for this first outing. I'll dial it back, next time. I was running av gas, BTW. 100+ octane (don't really know how much because it's not rated like pump gas.) I think it's about 104, or something like that.

I got my F.A.S.T. wideband air/fuel meter, but haven't used it yet. I don't have a welder, so, I have to go to an exhaust shop and get the bung welded in.

Thanks again, Speedytang, for seeing to it that I ended up with a unit that logs the data. I dodged a bullet, there... You da man... :)

Life is good...

Bill, in Conway, Arkansas
PS Doubleclick on the attached timeslip to enlarge it, so it can be read.
PPS Never got the 4.10 installed; these times were turned with a 3.55 SureGrip.