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Ignition Upgrade For Jeep 304 & 360 CID V-8 AMC Engines

Main Upgrade Information | High Performance Upgrade Explanations
Tips, Tricks & Troubleshooting | 1977 and Older Vehicles | Part Numbers

Modifications are largely formatting and non-technical. Some additional part numbers and prices from NAPA have been added.

The Jeep 304 & 360 CID AMC V-8 from 1978 to 1990 are eligible for this upgrade. The 304 & 360 CID Engines from '78 to '90 used the same Motorcraft distributor for all variations. (*If you have a 304 or 360 CID V-8, 1977 or older, I urge you to read this*)

There are three upgrades listed below:
1. BASIC UPGRADE: No modification required to any 'Hard' parts. No cutting of any wiring harness. Does not increase spark energy, just makes sure it gets where it's supposed to go and helps smooth out idle. No options and has to be done all at once.
2. MILD PERFORMANCE UPGRADE: A small amount of modification required. This upgrade builds on the BASIC UPGRADE for faster response times, better starting, and much higher spark energies.
3. EXTREME PERFORMANCE UPGRADE: A fair amount of modification required. This is an upgrade that should only be done after the second upgrade has been done.

Part Required Basic Upgrade Mild Upgrade Extreme Upgrade
Distributor Cap Base X X X
Distributor Cap X X X
Rotor X X X
Spark Plug Wires X X X
Ignition Coil   X X
Advance Springs   O O
CDI Ignition Module     X

The Motorcraft distributor type is one of the most dependable ever released from the factory. The distributor it's self is a very good unit, and can easily be tuned and used for even extreme performance upgrades.

Jeep used the small 'well' type distributor cap, short rotor, low energy ignition spark plug wires and low output ignition coil to save money. Those money saving items are the problem. The distributor cap design is left over from the 1920's. (WWI technology) The plug wires haven't changed in any distinct way since the 40's. (WWII technology) The ignition coil is still based on the oil filled units that appeared in the 1920's. (WWI)

The below described upgrades use as many stock, off the shelf parts, as possible, so they can be replaced at any parts store. This keeps cost and replacement parts availability problems to a minimum.
I also try not to get away from factory groupings. If I use all parts from the same year, then it makes it easier to remember where things come from. If you decide to go onto the second and third upgrades, make sure you print a copy of this article and put it into your service manual or vehicle papers.

Use this upgrade only if you intend to use your stock coil and wiring harness with no modifications.

Stock Jeep Parts To Remove: Distributor Cap, Rotor, and Spark Plug Wires.

From a 1979 Ford F-350 truck with a 460 CID engine: Distributor Cap Base (adapter), Distributor Cap, Rotor, and Spark Plug Wires.

Make sure you don't forget the basics, and get a good quality distributor cap & rotor with brass terminals or you are just wasting time and money with this upgrade.


These upgrades are designed to enhance the already formidable Motorcraft ignition system. This upgrade will surpass the GM HEI system by about 1-1/2 times.

Stock Jeep Parts To Remove: Distributor Cap, Rotor, Spark Plug Wires, Ignition Coil, and (optional) Distributor Advance Springs.

From a 1984 Ford F-350 truck with a 460 CID engine with ECC: Distributor Cap Base (adapter), Distributor Cap, Rotor, Spark Plug Wires, TFI Ignition Coil, and (optional) Distributor Advance Springs.

Make sure you don't forget the basics, and get a good quality distributor cap & rotor with brass terminals or you are just wasting time and money with this upgrade.

If you ask for the components from an engine WITH ECC (Electronic Combustion Control) you will get the square TFI (Thick Film Integrated) ignition coil, and the plug wire set with the correct coil wire. You will have to remove (cut) the stock coil connector from the wiring harness in order to connect the TFI coil. You will also have to fabricate a coil bracket, or locate a stock application coil bracket.

The TFI coil will work with ALL of the DuraSpark modules. It's an odd looking thing, but can be mounted in any orientation (even up side down). The TFI coil uses a full 12 volts, and doesn't use a resistor of any kind. The coil from a '84 Ford F-350 Truck with a V-8 engine (With-EEC). The coil runs about $15 to $45 in discount stores.

THE TFI COIL REQUIRES A DIFFERENT CENTER COIL WIRE THAN THE OLD TYPE 'CAN' COIL. The connections are different, so make sure the center coil wire included in your spark plug wire set is correct before leaving the store.

2B. Distributor Centrifugal Advance Springs
From: aftermarket supplier Mr. Gasket, P/N 925D (around $4.00). These springs DO NOT have to be installed when the upgrade is done. It is just a way to get a little more 'zip' out of your engine.

This upgrade will bring your Jeep ignition system into the mainstream 80's technology.

Once the cap, rotor, plug wires and ignition coil have been upgraded, then you can use some racing technology. The next HUGE jump in ignition performance is the CAPACITIVE Discharge Ignition (CDI).

All factory ignitions, and most aftermarket ignitions supposed to be upgrades for the Jeep are still INDUCTIVE discharge ignitions (IDI), including the extremely expensive and temperamental D.U.I. ignitions and all JACOBS ignitions.

Multiple Spark Discharge (A module upgrade, from Inductive to CDI) gives vastly superior ignition energy on all counts. Spark Duration, Spark Voltage, and Spark Amperage are all increased to the point were misfires are unheard of. The MSD Capacitive discharge module driven ignition will out perform the Inductive ignitions in all areas, from 100 to 1,000%. MSD is the biggest bang for your bucks.

The MSD 6 series units are the workhorses of the MSD product line, and there are several different versions of the 6 series unit available, depending on your intended application. The MSD 6A is a full CDI unit that is more than capable of operating above 15,000 RPM with your stock coil. There are Weather sealed Off-Road units, and Marine units for deep water fording operations.

The MSD 6 series units are compatible with all Motorcraft distributors and ignition coils.

The most common, MSD 6 series, units are 50 State Emissions legal!

Use Wiring Adaptor P/N 8869 to connect the Motorcraft distributor connector to the MSD 6A and 6AL harness. (Around $10.) This wiring pigtail keeps you from having to cut into the distributor wiring or the MSD wiring, and it keeps the distributor pick up coil polarity correct.

There is one for the marine and off road units with the Weather Pack connector, but the part number evades me right now. If you have a later model Jeep with a 'computer', there are harnesses that will allow you to use MSD and keep your computer functioning. By doing just that, you stay 50 State Emissions legal with the later model Jeeps.

You can browse the MSD website, or contact MSD by phone at, MSD Tech. 1-915-855-7123.

MSD hardware can be purchased at Summit Racing Equipment, phone number 1-800-230-3030.

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