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Discussion Starter · #1 ·
My 77 CJ5 with 304 has a completely stock ignition. I am thinking of replacing it with one of the aftermarket ignitions out there, DUI, jacobs, etc. along with throwing on some high-quality plugs and wires. I have read rave reviews and harsh bashes of both systems, but was curious if anyone had any good, objective opinions of the two, comparison wise--or of other aftermarket ignitions that are available. I'm not an ignition expert, so I'm leery of starting out on my own with a custom swap (GM hei or otherwise). Thanks in advance,

Measure once, cut twice...or is that the other way around?

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6,355 Posts
/wwwthreads_images/icons/tongue.gif There is a new aftermarket GM HEI to fit your 304 from Davis Unified Ignition. It sells for 350 rassbucknicks (yow!) Is farmin' that good? /wwwthreads_images/icons/crazy.gif

I never believe any statistics unless I've made 'em up myself.

Discussion Starter · #3 ·
i can only go by past experience, but i put the jacobs kit on my 94 5.2 dodge dakota and did not see or feel any difference. i feel it is overated. i am going to go with a dui system for my 85 cj-7 with a 401 simply because it is cheaper and the prestolite dist on my 401 is junk. just my opinion


Discussion Starter · #5 ·
what system do you have now? if it is a motorcraft, keep the distributor and add a MSD6A. i have found this seems to give good bang for the $$$. if you have points, then ditch the whole setup for a DUI, or a MSD distributor and box. there are some faults to an hei setup, but they are inexpensive and fairly reliable.


/wwwthreads_images/icons/smile.giflet it snow/wwwthreads_images/icons/smile.gif

Discussion Starter · #6 ·
Deano, I have the stock Motorcraft distributer with an MSD 6AL ignition box. Works great. I left the stock ignition control unit in place so if anything happens to the MSD all I have to do is plug the stock one baqck in. Redundant ignition!


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6,784 Posts
You didn't say if you had points, or one of the oddball prestolite distributors.
Ether way, find a distributor out of any '78 or '79 AMC, or any Jeep anything with the AMC V-8 from '78 or '79.
The one you are looking for is the Motorcraft distributor.
(If it has a giant vacuum advance, and a reluctor that looks like a giant spider, pass it up)

That distributor should drop right in your engine, and not cost the $300 or more aftermarket units do.
(BTW- most aftermarket distributors use the Motorcraft type pickup coil and reluctor anyway, so why spend the bucks?)
Salvage yard prices are about $25, or the auto-jerks stores want about $50 with a $50 core charge.
Equip your new distributor with mustang centrifugal advance springs, and a new vacuum advance.
(This gives you electronic pickup, vacuum advance & centrifugal advance)

Get a coil, distributor cap base, cap & rotor for a '79 Ford F-150 pickup with a V-8.
Pay the extra bucks and get brass terminals.
(This gives you the wide HEI type cap and high output HEI coil)

Get the plug wires from a '79 Ford F-150 pickup with a 351 Cleveland, and they should have the correct ends for the cap, and be long enough.

The Auto-Jerks stores sell '79 DuraSpark modules for about $20, and with the distributor and coil, it's just shy of a plug in upgrade.

If you really want some kick in your spark maker, get a MSD 6AL for about $170.
The MSD 6AL is a capacitive discharge ignition, and a multiple spark discharge unit.
It will give about 5 times the spark energy at the plugs with a stock Ford coil, and about 10 times the spark duration.
It has a built in rev limiter, handy tach terminal, and the provision for a ignition kill, for say, low oil pressure or overheat...
MSD units don't change the dwell or timing like other units. (Many of the aftermarket units let timing and dwell 'drift', not a good thing)

E-mail me at [email protected] if you want a wiring diagrams, pictures and directions.
I was just finishing up an upgrade article on this very thing. E-Mail the grand high poo-bah at Off and see if they will post it as a tech article.

So many cats, so few recipes...
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