Dual plug heads

[Heretic]

on my old one, I used the crane HI-4 single fire ignition and rev-tec coils. I chose the coils because because that is what my local shop had in stock. They were 3 ohm, and would work with the ignition.
my next one will use a single ford 4.6L V8 coil. They have duel coil packs, and the ratings are right. A single one of the duel coil packs from one of the newer mustangs will work, and the size will be easier to deal with than the duels

[viking-bob]

Hi there
Great string on Dual plugs.

I run dual plugs on my big bore stroker with Dyna electronic ignition. and black Dyna dual coils.

I’m trying with different ignition adjustments but I can't (don’t know how ) find the right position.

Any suggestions?

My setup is:
Big bore s&s cyl, s&s crankshaft, Andrews C camshaft, dual sparks with dyna's ignition., Black dyna coils, accel yellow spark cable half electronic ignition with advance kit, s&s super B carburator ,1 3/4"drag pipes

[83 shovel]

is it common to use 2 diffrent size plugs from left to right side??

[gliderider94]

25 years of engine design experience allows me to support what junior has said about burn characteristics of dual plug heads. There are however a few aftermarket head/piston combinations that are designed specifically for use with such an application and will deffinately provide noticeable perfornmance improvement. The problem with dual plug and piston sets is that in order to realize the performance potential possible with such an application the compression ratio goes up significantly, which accounts for the added power as much as the second plug does. This however will bring on a whole new set of challenges just trying to get the damn thing started on a regular basis without chewing up starters. One work around is to change the gear ratio on the starter pinion gear to clutch basket gear. I lot of guys I know who are running dual plug heads have also gone to the mating piston setup which creates the higher compression but instead of running the second set of plugs they are filling that hole with push button compression relief valves (Jim's makes and excelent set). The higher compression will get you a noticable power upgrade and the relief valves will save you a shit load of push starts.

[KPBR]

I found everyones input very interesting on this topic. I have an evo sportster with dual plug heads and soon before I was hit on it I had rewired it with points and ran only the top two plugs. (thought it was cool for people to see plugs with no wires) I didn't notice a lot of difference in power, although I was wondering if its possible to run dual coils with my points? And if so, would my motor relate and run more efficient/longer life? Any advice would be appreciated.