I am new to the whole automotive world, so if I say anything stupid I'm sorry. I have a '83 CJ7 258 I6 4.2L. I have been experiencing some problems lately. When shifting into gear it isn't firing, the gas doesn't seem to be there. Originally I was told it was the carb. with all the emissions crap added in the 80's but after changing it to a holly carb. and bypassing all that the problem is smaller but still there. A friend thinks it could possibly be the distributor box. He said he read that there have been problems. True?? He suggests going to the DUI system and once again bypassing it. I just want a dependable jeep first and then add extras. Any suggestions. It's hard to describe the problem but any help is appreciated.

-nebwheeling  

have ya reset the  float level in the holley?  

no, how do i go about doing that?  

maybe a cracked vacuum canister?  They are getting pretty old.  

If it's a new carb there is no reason to doink with the float level. If it has been monkied with you may need to. However, start simple. Check everywhere for potential vacuum leaks and plug them. Next check the distributor cap and rotor for cracks or damage. Even the smallest crack will cause your engine to run poorly. Then, lastly, dive into the ignition. As mentioned, the stock ignition is less than stellar.  

i haven't ever gotten a new holley out of the box that had the floats set correctly,

does it idle when parked? die when the brakes are applied?  

I used a chevy 4 prong module,tossed the crappy box,used a tfi coil,dist cap,cap base,rotor,plug wires from a 86 ford 460.I think you can do this swap or something similar with your 6cyl.Dont forget to re-gap yor plugs!! CJ's had the Prestolite ignition, as you know now, and it's not really upgradeable easily.
The distributor has several weak points, and it uses a true Hall effect trigger.
The are a few aftermarket ignition modules that will work with a true Hall effect trigger, but they are UNGODLY expensive!

You have a couple of options here, so you will have to know a few things to make an informed decision...
1. The distributor you have will need to be replaced.
The distributor you choose will need to use a standard magnetic trigger.
I won't bother with the ones that aren't using a pretty standard magnetic trigger and vacuum advance.

2. The distributor does two things,
A. It signals the module to fire the ignition coil.
B. It makes the high voltage go where it's supposed to, when it's supposed to get there.

3. You will need an Ignition Module.
The ignition module is the switch that turns the ignition coil on and off.
Every system will need one. The Prestolite you have will not work with any of the common systems.

4. The Ignition Coil makes the spark energy that travels through the distributor cap, then to the plugs.
The coil you have is not suited for use with a modern electronic ignition.
..........

Now, for your choices...

Distributor,
1. You can use a Motorcraft distributor out of a '82 Jeep CJ-7 with 258 (4.2L) engine.
It will drop right in and work perfectly with your engine.
Remember, the distributor is actually an engine accessory.
Jeep used this distributor from '78 to around '90, and although made by Ford for use in Jeep, it's designed and 'Curved' to fit in your AMC engine and work correctly.

You will also need a module and coil, but we'll cover that later...

2. You can purchase an aftermarket distributor for your engine.
Several companies make distributors with a variety of designs, but you would be well advised to use one that rebuild parts, caps, rotors, pick up coils, springs, ect will be available for at any parts store with out special order,
That only leaves two, Motorcraft and GM HEI.

3. The only distributor that has an upgradeable cap and rotor is Motorcraft.

4. The Motorcraft distributor is available at the local discount auto parts stores as new or remanufactured.
5. It was designed to work specifically in your engine.
6. You don't have to change any gears or parts.
7. The cap and rotor are upgradeable, or in your case, will be the upgraded parts from the start.
8. You can use more than one brand of module with it.
You can trigger any of the upgrades aftermarket modules with it, Like MSD.
It is a very reliable, well built, well designed distributor that will serve you well for years.
............

Module,

The number one, 800 pound gorilla of common ignition modules is the MSD 6 series true Capacitive Discharge Module.
This isn't a fair comparison, using a true CD ignition and comparing it to a regular factory type ignition module is like taking a Nuke to a fist fight...

Two heavy power wires, one activation wire, and with an adaptor the distributor plugs directly into the Motorcraft distributor.

Your other choices are,

The factory (Ford) DuraSpark module.
This thing has a couple of features that are note worthy,
BUT,
To be quite truthful, in real world use it's reliability is questionable and it's just plain more difficult to wire if you build your own ignition system.

The Factory (GM) 'HEI' module.
This module, when properly supplied with a heat removing mount, is reliable and about as strong of an output as any of the factory type modules.
Five wires and you are connected.
If you are going to use a factory type module, this is the easiest.

You can also use the factory Chrysler module, but it's not really suited for this kind of use.
...............

Ignition Coils.

Since you need to start from scratch and buy a coil that is going to work with a commonly used ignition system, I'd recommend an E-core coil instead of the canister type coil most commonly used on Jeeps.

The E-core coil isn't oil filled so it can be mounted at any angle,
It's design allows for more amperage and longer spark duration,
Both primary components in usable spark energy.
Both GM and Ford used them for several years, so getting one for years to come (availability) will be very easy at any discount auto parts store.
Both of these coils are compatible with any of the factory or common aftermarket ignitions.
...............

One common alternative is the GM HEI distributor out of a Chevy 250 CID I-6 Engine.
This is a 'Junk Yard' alternative  

Have you checked for vacuum leaks? Does it run better under full load? An engine running @ idle no load will run with a vacuum leak, but put a small load on it and it will die. Think of a vacuum leak as excess air which equals more air to fuel because the carb does not see that air to compensate for it. Thus a lean burn and misfiring. I would try capping all of you vacuum lines except for the distributor to the carb. Check that line thuroughly. If it get better, than its a vacuum line/ canister or something along that path. If not, then ignition timing, intake manifold leak, carb adjustment, or spark power would be the next things i would look at.