dual spark heads

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waggl1

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So ive found a pair of dual spark plug heads for a 440BB. What kind of electrical system will I need to run this?
 
Never head of such, at least for a B/ RB. Some of the '70's hemi pro stuck guys were experimenting with dual plug heads. Two distributors. "Somebody" made a dual dist. gear drive setup

I SAY WE WANT PICCCHHHURES!!!!

EFI_16plug_drysump_HEMI_2.jpg
 

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oh my apologies...kinda new to the mopar world excuse my lack of education. I just saw the two inserts on the top of the head so I assumed they were dual spark plug heads.
 
waggl1 said:
oh my apologies...kinda new to the mopar world excuse my lack of education. I just saw the two inserts on the top of the head so I assumed they were dual spark plug heads.
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They are Dual Plugs, for a 426 Hemi.
 
hmm well maybe this person needs to get their facts straight they said to me they were for a 440. Thank you for pointing this out that saved me money.
 
but anyways so if you were to run a dual sparkplug system in the heads what kinds of pros/cons will I run into with doing that kind of setup? Again new guy here so I will take all suggestions into consideration.
 
The average carb street engine there isn't really any advantage to dual plugs. Ford used it for years on the 2.3L ranger motor and chrysler is using it on 3rd gen hemis and later 4.7's, but for all normal purposes 1 plug per cylinder will get the job done just fine.
 
If I remember right the earlier dual spark plug system used on production vehicles was more for emission than for performance....I remember an 86 Datsun used them on the 4 cylinder engine.....The plug on the intake side was for combustion and the one on the exhaust was used to help with the burning of exhaust gases....No performance gains...The Rangers that used that on the 2.3-2.5 4 cylinders were slugs.....
 
those guys took along time to get dual plug motors to run right, big pain in the ***... i doubt your gonna be on fuel or even alky so just get a 6al or -2 and be done with it. on stock heads...

and also his ad said hemi heads all over it
 
I don't remember if they were EVER exactly successful. I remember some of the pro stock guys went back and forth with 'em in the 70's, used to see some run with the dual plug heads but the second plug "plugged."

They do this with aircraft, some older gasoline fire trucks, etc, but I always understood it was for reliability
 
67Dart273 said:
I don't remember if they were EVER exactly successful. I remember some of the pro stock guys went back and forth with 'em in the 70's, used to see some run with the dual plug heads but the second plug "plugged."

They do this with aircraft, some older gasoline fire trucks, etc, but I always understood it was for reliability
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i think landy got pretty good with it but not really better than a single plug...
 
:dontknow: I think the dual plugs had some issues with dual 'flame propagation' causing problems. IDK, something about the flame fronts crashing into eachother .
 
Stage V made dual plug heads for the B/RB engine Hemi conversion.
 
Thank you for the input on this situation. I guess its single plugged heads for me haha. I just thought it would help being an advantage in running a turbo but now im thinking itll just be a bigger hastle.
 
waggl1 said:
Thank you for the input on this situation. I guess its single plugged heads for me haha. I just thought it would help being an advantage in running a turbo but now im thinking itll just be a bigger hastle.
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no offense but if you cant tell the difference between hemi and wedge heads your not ready to jump into the world of boost... you need some time behind the wheel of a stock slant six car to learn maintenance and simple upgrades and the effects (good and bad). after that maybe look into a big block or small block, or build a slant for boost without the boost for awhile.
 
Aircraft engines use dual plugs because they run separate ignition systems. Also the dual plugs may help get all of the combustion gasses to burn in those huge diameter cylinders. My O-320 is 320 cubic inches on 4 cylinders. Before takeoff pilots set the RPM to 1700 and turn off each ignition system to check if the other mag is working and noting the RPM drop. The engine loses about 100 RPM on one ignition. Aircraft engines are very low performance as far as how they are built. Mine has 7-1 CR and runs on 87 octane non-jokenol car gas.
 
805moparkid said:
no offense but if you cant tell the difference between hemi and wedge heads your not ready to jump into the world of boost... you need some time behind the wheel of a stock slant six car to learn maintenance and simple upgrades and the effects (good and bad). after that maybe look into a big block or small block, or build a slant for boost without the boost for awhile.
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We all have our opinions. When it comes to mopar im not a big know it all guy so its a little different for me but as far as what my experience in the performance world goes...ive had a supercharged small block camaro for a few years granted it was fuel injection Ive also been part of a small shop building diesel performance engines. So quite honestly mopars i didnt care much about but now i sold that car and this one fell into my lap so im trying to "broaden my horizons" so to speak. I mean im sure there are things in the automotive world you cant decipher the difference between...but we all learn :) and become better.
 
mcnoople said:
The average carb street engine there isn't really any advantage to dual plugs. Ford used it for years on the 2.3L ranger motor and chrysler is using it on 3rd gen hemis and later 4.7's, but for all normal purposes 1 plug per cylinder will get the job done just fine.
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Any hemispherical head will run better with dual plugs and this was indeed a good idea that because of cost and bulk wasn't implemented on the Street Hemi. Chrysler engineers designed those castings from the start with this capability, although I think some were not cast with the needed boss in place. I am not an expert on nor a fan of the 426 Street Hemi for several reasons, but I can attest to the benefits of dual plugs on hemi combustion chambers.

You can prove this easily if you have a way to constant load the engine and disable one of the ignition systems. Power will drop. On aircraft engines they do a "Mag Check" before takeoff and it is required to have a drop in a certain range of rpm and for the drops to be even. If one mag is dead the engine quits. The fact that there is always a drop means that the engine runs less efficiently on one than on both.

I had BMW motorcycles for years and when gas got crappy in the eighties we had detonation issues. Some guys added avgas or ethanol. Some people put in spacers at the cylinder base to lower compression. But what worked best was having the heads machined for twin plugs and a second coil and wire set added. The engine then made more power and detonation ceased.

The Harley guys did this for awhile too and then the Evo came out with a different combustion chamber design.

Is the hemi combustion chamber particularly good for power and efficiency? Not so much which is why it has gone out of favor for pentroof and high squish designs. The Modern Hemi has a shape that is not hemisperical but hourglass shaped.
 
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