I've been running the standard MP electronic ignition kit in the Charger since I pulled the 318 and swapped in my first 440 in 2001. I've gone through several spark boxes, some orange, some parts store replacements, some used ones. I have had several cars and trucks go through my hands over these past 10-11 years and there tends to be some "sharing of parts".
The orange spark box has a spotty reliability record. Twice I have had spark boxes work fine when I shut a motor down and fail when trying to break in a new motor. JUST the wrong time for a pivotal part to crap out, huh? I've had my head in the sand as to ignition upgrades, but have heard a few tidbits here and there, from Mallory to MSD to Firecore.... I was curious as to what benefits and/or options these kits offer. I recall some talking about rev limiters, ignition spark retard for faster cranking on startup, etc. My question is to those who use these systems. What are the features that you looked for and settled with? My combo is a 3900 lb '70 Charger with an aluminum headed 440/493, 10.8 to 1 and a MP '509 cam. Thanks guys.

The later model Mopar Perf distributors supplied in the kits have a very cool feature that allows you to shorten the slots reducing mechanical advance--thus you get to set initial advance higher without the mechanical adding too much later--the more initial advance allows any HP unit with a cam to idle MUCH better but then limits the amout of advance the weights add in as RPM goes up--having your cake and eating it to. a BIG plus.
The Mopar Chrome box is an amzing unit WHEN coupled with a high output coil like the old yellow Accel--This makes a killer package that will ignite 12:1 at 7500 rpm easy!
The orange box is a junker--parts store units are better
To answer your question there are guys like FBO that offer super boxes according to them--I have never run one.
MSD is about the best you can do no matter how you trigger it--it WORKS It WORKS GREAT! Firecore does make killer wires but so do many others--fresh cap, rotor, quality wires routed right, Chrome box with hot coil or better yet MSD like a 6al can't be beat --NO ignition is worth a darn if not grounded right--quality grounds at many places is the key to no trouble
Again..any Mopar box HAS to be grounded well or else--no paint behind it, star washer, etc get it grounded or it will run like poo

Petronix II, or Petronix III if you want the rev limiter, Petronix wires,Petronix Flame thrower II coil...........

I look for a good quality distributor first.
features like adjustable mechanical advance, and if a street car, vacuum advance. The cap and rotor are really the limiting factor of the ignition system. The larger cap/rotor design is a better design, but won't fit most applications, and I don't know any boxes that take advantage of them. For example, the MDS only does multiple sparks below 3,000 rpm. Why, because at higher RPM there is less time that the rotor is under the correct terminal, and you don't want to accidently cross-fire the next cylinder early. That is a big reason new cars use coil packs.
This gets back to quality, and having the pickup, rotor and cap phased correctly. I have an old Mopar electronic ignition conversion (does not have the adjustable mechanical advance), and the cap/rotor phasing was way off.
I have not bought a new distributor in over 10-years, so I can't say whos unit to use.
In a basic sense, a stock distributor that is curved to your application and a replacement ignition box and coil would work fine in most cases. I like using the Capacitive Discharge (CD) boxes with the multi-spark, and rev-limiter features, a few examples MSD 6-AL and Crane HI-6.
These reduce the chance of a mis-fire when the air/fuel mixture is not optimal.
For performance applications, I like the "E" core coils, but most of my street cars just use a canister style coil. Most of the performance ones are going to be good as long as it matches up to your ignition system module/box. I have been running the old Jacobs Energy chrome coil for years because it has been trouble free. I think it is slightly higher current, lower voltage (0.6 ohm, 6.4mH, 90:1 turns, 40KV) than the MSD Blaster 2 (0.7 ohm, 8.0mH, 100:1 turns, 45KV.)
Jacobs went out of business.
On the Charger (400 stroker) I use a really old Mallory Uni-lite distributor as a trigger for a MSD 6AL box and a Crane PS91 E core coil. The Uni-lite modules have been know to go out. Mine went out last year, but it was almost 20-years old. The Convertible (440) has an old (now discontinued) Accel 71300E Billetproof distributor. One reason I bought it is that it resembles the stock dist, and has all the electronics inside. It has worked really well with the Jacobs coil. My truck (360) has my Mopar distributor from an old conversion kit, that I had to re-index the cap, and I use it to trigger a Crane HI-6 box, again using a chrome Jacobs canister coil.

You can get as many features as you can afford.
At the top of the heap I would put Electromotive and for a couple of thousands you can get a completely solid state ignition with individual coils or one for every two plugs. Advance is strictly electronic and the timing is off a wheel on the crank.

Now for the underfunded like me there are several good ones. The MP high perf distributor is essentially a Mallory and the adjustable advance feature is great. No one can argue, either, with MSD's line of distributors. I am old school and am using Accels and so far no problems at all. I'd put a Pertronix conversion of a stock distributor a layer or two below because a better advance curve can do wonders. That means for a Pertronix conversion you should really rework the distributor to have a better advance curve.

For spark boxes there are four that I would trust. My favorite is the Accel 300+ box and coil. It's digital, compact, uses less amperage than some of the others, has a built in settable rev limiter, and has lasted 130,000 miles under the hood of my '93Sub where it is really roasty. Like, you can't put your hand on the hood after driving. In second place is the MSD 6 in any of its forms, my '64Dog is running a used 6A or 6200 that I bought on the 'bay for $40. Third because I haven't used it is the Crane HI-6. I think it's a pretty super box. Fourth again I haven't used it is the Mallory Hy-Fire whatever the latest version is. I would use the matching coil with any of these boxes. I use an old Jacobs chrome coil on my '64Dog because it works.
The MSD Street Fire is like the 6A except with less spark energy available, made in USA and may be a good choice but with 6As going for $50 used I can't get too excited about it.

Summit and ProComp may be great but I wouldn't put my trust in them because they are built down to a price in China AFAIK. My road trips are usually 600 miles and I wouldn't want to be in the middle of nowhere (Monument Valley, for one) in the middle of the night with one.

For wires most any spiral core wire will do, I use BWD wires in my '93Sub, a combination of Accel and MSD wires in the Dog, and Magnecor in my higher end vehicles. If you ever install a set of Magnecors you will know what I mean. They're the nicest plug wires I have ever installed. They cost more but IMHO they're worth it. Also you should go to the Magnecor website to find out how plug wires really work. Hint: DC resistance, ohms/ft, has about nothing to do with it.

There is my ignition wrapup.
R.

That is the inductance of the coil in milli-Henrys.
It is a combination of the core and number of windings. The higher the Henery number the slower the current can change, but it should create a larger magnetic field which can produce more energy.
Coils with larger inductance values are used with conventional ignition systems, because the spark is created by the collapse of the magnetic field.

I found this link interesting:
http://linuxfan.org/~ipdown/mybrick/automotive/IgnCoilAnalyzePrez.pdf

Dont forget the MSD E-Curve.

I like and run the MSD 6 box. Its reliable. I believe the multi sparks help starting, idle and low RPM operation. It is also common enough that most towns have an auto parts store that stocks them for an emergency. There's no ballast. Depending on which version you pick, they have rev limiters and other features.

For the distributor, any distributor in decent shape with the right curve for your engine should be good. A re-worked stocker is fine or a higher end adjustable. The smaller cap styles have less voltage capability then the high end big cap style. Adjust plug gap accordingly. Plug gap and cylinder pressure largly determine the secondary voltage. More gap and more cylinder pressure make more voltage... up to the max capability of the ignition. Even though a MSD + Blaster coil may be able to produce 45 kv with a smaller gap, actual voltage will be lower.

With a stock style distributor, run stock type gaps - .0035" - and the cap/rotor should live a long happy life. With a higher capability distributor, you can open up plug gaps... although I'm not sure there is much benefit in the big gaps.

Back in the day when emissions regs were getting a lot tougher GM developed the HEI and used gaps as big as 0.055". It decreased unburnt hydrocarbons.
Drag racers found out that running a larger gap made them go faster if the rest of the ignition system could handle it. The advice was to open up the plug gaps until you started going slower, then back off a little.
If you think of the starting point of the flame, anything you can do to make it start bigger is a plus. Big gaps do that.
R.