Spark plugs, wires, gap?

[MOPEkid]

I'm soon going to be putting a Mallory HyFire VI-A box and a reman'd electronic distributor in my '70 Duster 318 and I also want to replace my plug wires and spark plugs. It seems the general consensus is that Champions are the best in old Mopars, and I think I'll go with those. I've also heard that with a high-power CD MSD-type ignition you can set the gap larger than OE spec for a bigger spark; is this true, and how big should I make it? And about the wires, I haven't done much research on them, but what would be the best ones I could use with a stock Chrysler distributor cap?

[dgc333]

There are as many choices for wires as there are opinions of which is best. My recommendation would be to stay with a reputable brand and the ones with spiral wound cores, they will last longer. Don't get hung up on wire diameter size the only thing that is different is the thickness of the insulation which may give you some additional abrasion or heat resistance. Also, don't get hung up on the resistance per foot either, as long as they are a reputable brand they will be more than adequate.

I have headers so I like the universal cut to fit your self but if you are still using manifolds then the pre cut will work great.

[dwc43]

Don't forget the plug wire sleeves from DEI if you have headers.

To set proper gap, keep adjusting the gap wider till you pick up a high speed miss. Then back it off by .005 till it goes away and reduce it an extra .003 just to give you some room for wear.

[bobr]

I've never found any power in a wide plug gap. I set mine at .040 and forget about it-even with an aftermarket amplifier. -Bob

[rumblefish360]

DGC nailed it, DW fine tunes it bobr tells it like it is, on a general level, it isn't the biggest gain you'll find. Mileage should increase a bit and power should be well delivered by compare to an older system. The gap recomended is a good start point.

When it isn't up to par (The older system) there is a big difference in the all around feel.

I installed a MSD 6 and coil with a OE distributor and found that I could go to .055 on plug gap, but that is way wide and not needed. .050 is plenty wide.

[peg leg]

Are like hair. Everybody has some.
OK, for wires, Taylor 8mm spiral wound are excellent. Buy then precut, in your favorite color, with your preferred plug end angle, or cut them yourself. I prefer to cut and route neatly. Really good strong boots and brass.
Champions, yes Mopars like Champions, set at 0.035".
I bought the straight plug end to give me good header clearance.

[MOPEkid]

So would you all agree .045 would be a good gap? I'm not sure if I'm patient enough to set all the gaps, put all the plugs in, run them for a while, then take them all out again and reset the gaps. I do also think my old points system isn't working too well, as I'd sometimes get serious wobbling on my tach when holding the RPM's around 2000-2500. Also my idle was kind of "shaky" no matter how I adjusted the idle mixture.

[TrashedCharger]

At this altitude, start at .040" and go from there man.

We ditched the factory electronic ignition in my friends '73 Charger with his fresh 360. It's a Jacob's Electronics Pro Street (pre-Mr.Gasket), which I think is good up to 65,000 peak volts.

It has a stock distributor, blueprinted and recurved with a brass conductor rotor and cap. We are running them through the Taylor spun core 8.5mm, cut to fit wires with 135 degree boots to clear the headers. I would suggest 135 degree boots with a good set of retainers made for 8.5mm wires.

I believe he's running Champion R numbered (hotter) copper plugs to make due with the headers and the little bit of a cam that the engine has.

We were told that we could go .050", but we were having trouble with misfire at idle on vacuum advance at .050", even a little at .045" We ended up backing them off to .043", which is where we noticed the best fuel economy and throttle response.

This was also for a .030" over 360 with a cam that has just enough overlap to be heared at idle with a 4 bbl.

Your ignition should be plenty for that 318 with a .040" gap up here.

[cageman]

Yeah, plug gaps are like opinions, I run .028, in everything. They last a long time too, and never a miss fire. Big gaps allow for the path of least resistance to happen, and that could be inside the dist cap, the plug wire next to the one that is supposed to fire, or the valve cover, or the header tube, or the side of the plug, instead of the little tab that it is supposed to go to.

[valiant64]

I run .035 gap on Champions, use a good heavy (Mopar) dist cap with brass contacts- not the cheapo Autozone crap with the aluminum ones. A good quality rotor, and a good supression type wire such as Taylor/MP or even Napa's premium Belden wires will be more than adequate. No need for pricey drag race wires like some of MSD's or Accel's stuff.

[MOPEkid]

All right, I'll play it safe and go with .035, although I may try .040 if I have the time to test it. The cap/rotor I have in the new distributor now looks to be of good quality, it has brass contacts and the rotor is pretty solid-looking.

Along with the new ignition system I may try to re-jet my old BBD as it runs like crap (stumble off idle, not enough torque for burnouts, kind of weak mid/top-end, 'unsatisfactory' gas mileage). It's probably too rich, but I have to read the plugs to make sure. I originally wanted to put my ThermoQuad on there but I don't know if I have time anymore for a 4-bbl. swap. Maybe once school starts and I'm not working...

[5spdcuda]

Everyone has opinions, this is what works for me. CD type ignitions like a wider gap than induction [ ie. stock type]. .035 for induction type, .045 for CD. Champion used to make a really good plug. The company was sold some time ago and I think quality both electrically and in terms of mechanical construction has slipped. I have switched to NGKs and have had excellent results with them. I run NGK BCP6ES gaped at .045. My ignition is an older Crane CD. My plug wires are Moroso precut Blue Max, cheaper than most and excellent fit and quality.

[triggerbear]

I have allways run accel wires but allways 8mm. just a few more bucks then parts store brands. I also tried to stick with champions but also feel quality has dropped in recent years, so ive been running autolite platiums for that last 5 yrs. since switching 2 autolites i have never had a fouling problem.