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JeepHammer 03-01-2012 09:37 PM

Low Cost Fuel Injection Distributor For AMC V-8 Engines
Do you need a low cost, Small base circle distributor for your AMC V-8 for fuel injection?
Something that doesn't get into the power steering pump and doesn't stick up like the HEI distributors do?

Follow along and we'll get you there for CHEAP!

(As far as I know, this hasn't been published anywhere before, so when it catches on, expect it to show up in the 'Jeep' and 'AMC' magazines...)


This is what I'm stating with, a Breaker Points distributor from a '72-'73 Jeep CJ 304 V-8 engine,
Or '72-'74 Full Size Jeep 304 to 401 FSJ engine.

If you choose to pass the Junk Yard search,
Then buy one reman for about $50 from the local parts store and start with something clean and tight.

Your basic breaker point Delco Remy


There is plenty of room for the 7 pin GM HEI module under these housings.


This is to prove that any old grimy piece of crap can work for this particular purpose if you have the know how...


First Things First,
Put the rotor on the top of the distributor, and drill or paint a 'Divot' or 'Dot' so the gear gets back on the shaft with the 'Dot' and rotor nose on the same side...
If you have a real Delco gear, it will have a 'Divot' already, but some reman distributors don't have them and you can make your own.

Then need to tear the distributor down to 'Nuts & Bolts', this is a pretty easy operation,
You first drive the roll pin out of the distributor gear, taking care NOT to loose the roll pin or housing shims,
Also notice the 'Divot' in this photo.

They you pull the distributor gear off, DO NOT loose the pin, shims between gear and housing or the gear!

If you are starting with a Reman distributor, this should be simple,

If you have an old crusty one like this, you might have to soften the crud stuck to the distributor shaft, which can take some soaking and more than one try to get the shaft out of the housing.
Each time you try, you will shave a little more crud loose from the shaft...
And eventually it will come loose without pulling the top shaft bushing...


Now it's time to DIS-assemble the vacuum advance and breaker points trigger plate...

DO NOT lose the little 'Wave Ring' 'C' clip used to retain the advance plate, you will be reusing it again...
This is what we call a 'Jesus' part, if you break it or lose it, it's VERY hard to replace, so take care when you are removing it and DON'T LOSE IT!

LOCATION, and this is really hard to photograph,

Find the ENDS, work an end out of the groove and 'Unscrew' the WAVE RING GENTLY!

RIGHT is the Wave Ring style Circle Clip, And you will see why it's called a 'Wave Ring' when you get it off, the 'Warble' bends in it are factory,

LEFT is a way to keep those small parts for the gear install together and keep them from getting lost...


Now, there is a rubber wire strain relief Grommet in the bottom of the distributor, and you will need to take the wire loose form the breaker points, or feed some extra wire up though that rubber Grommet,

Then you can lift the advance plate out of the distributor body.
There is usually a 'Ground' wire attached to one of the vacuum advance screws

The only POWER TOOLS so far is a Dremel tool or a Round File!


Now, you need to mark the trigger point, find the contactor on the breaker point arm and mark the location on the center bushing...

Here is a set of breaker points, same AMC V-8 Application, with bright RED contractor, Shows up better in pictures...

And mark that contactor point,
In this case, it's the 'Sharpie' mark on the plate, and although the picture doesn't show it up,
There is also a small file notch on the bushing collar.
That scratch is there so when the 'Sharpie' mark disappears during cleaning, I will have orientation.

All you have to do is fit the old breaker points on the plate again, find your location, and mark it again!
(Good reason not to throw things out until you are done!)


I usually scrap the grease catch ring (it doesn't work, obviously... See picture above...),
And I get rid of the 'Ground' shown on this plate, we aren't using anything that needs a 'Ground', so it's just in the way...

One thing I've noticed about these 'Jeep' advance plates,
The grease collar is STUBBORN to get off...
Most plates with a 'Delco' part number stamped into them come right off, but these are often induction welded to the plate, so a Dremel tool is usually the best way to get the collar off.

Something else,
Delco stamped plates usually have the 'Ground' spot welded to the bottom, where these often have it right up on top in the way when you are doing this conversion...

Once this plate is cleaned off and the trigger point is marked,
We are ready to rebuild with a 'Breaker-Less Trigger (Stator)...

JeepHammer 03-01-2012 09:38 PM

To modify this trigger so you can use an BREAKER-LESS trigger, it's going to cost you about $15 in parts.

This is no big secret, I've been doing it since the '70s, and it's pretty easy to do...
Just takes some time, a 'Dremel' tool and/or round file.

I start with CHRYSLER triggers from about '76 full size engines.

This trigger is VERY ACCURATE, and with fuel injection, that counts!


These are the three types of triggers sets you will run into with late '70's Chrysler vehicles,

TOP is just the Stator,

LEFT is a single trigger on an advance plate,

RIGHT is a dual trigger with one trigger slightly Advance Retarded from the other.

For an HEI conversion with vacuum advance, you will use a single trigger.
For FUEL INJECTION, you will use a single trigger.

For a trail redundant Dual Ignition, you can use the dual trigger model, but not with fuel injection with Electronic Spark Control (ESC) or Electronic Spark Timing (EST) that works with some of the better fuel injection systems.

The LOWER LEFT PLATE mounted version makes for easier mounting, IF You can clearance the thickness of the plate...

The Factory Advance Plate you are working with is FULL OF HOLES, cut outs, ect,
So sometimes this plate comes in handy for mounting...




As long as you keep the reluctor CENTERED over the hole, you can use any point on the 'Reluctor' to trigger the stator...

The position the breaker points triggered from is no good for me, the stator won't mount correctly since the vacuum advance hole is in the way...

Stator in the second position doesn't work either, still interference from this swiss cheese advance plate...

Still not working,


Center punch the likey hole positions, but don't drill just yet...
Need to see how it's going to line up with the actual shaft and 'Reluctor'!



With springs, weights and CRUD removed from the shaft, the ADVANCE HEAD should slid off the shaft with little or no problems...

FOR AN IGNITION USING DISTRIBUTOR ADVANCE, "Tach" Signal FI, or Building A Reduced Diameter HEI...


YOU SHOULD BE ABSOLUTELY SURE you need more advance and the engine can tolerate it before you start cutting here!



This is the advance head in the FULLY RETARDED position...

That is all that's required for locking down the Centrifugal Advance for Spark Controlled Fuel Injection.



I use a Dremel tool, metal burrs and grinding stones to get the 'Reluctor' to slip over the breaker points cam lobes, and I try for a 'Press Fit' so I don't have to use a screw to hold it in place.

This shows,
LEFT, A modified Reluctor going onto the factory beaker points lobes, notice the 'Points' of the 'Reluctor' line up with the beaker point lobes?

CENTER is an unmodified Chrysler 'Reluctor',

RIGHT is the complete conversion, Press Fit, but I usually use 'Locktite Red' stud locker on them, just in case...

Here is another picture of the parts...

LEFT, Delco breaker points advance head cam lobes from the bottom,

MIDDLE, Off The Shelf Chrysler Reluctor from '76 V-8 engine application,

RIGHT, Reluctor ground and fitted to the Delco advance head with Reluctor points lined up with cam lobes.

This part is done and ready to install in the distributor again.


Now that you have the 'Reluctor' Test Fitting on the advance head,
It's time for a test fit to see if that 'Stator' you marked earlier is in the correct position...


'Reluctor' clears advance plate, Shaft Spins Freely, No Issues So Far...

With STATOR in place, the Reluctor wants to rub on it's bracket.
So I need to push up the Reluctor a little more for clearance,
And it's perfectly acceptable to grind a little off the bottom for clearance since the center of the Stator is so far up the Reluctor, you aren't loosing anything,

This is hard to see, but the Reluctor BARELY reaches the top of the center 'Tooth' of the Stator.
The Reluctor Most Certainly needs to go up a little, and that might solve BOTH issues at once...


Now, Reluctor is driven up on the cam lobes a little, and it's REALLY TIGHT,
That made all the difference in the world!

Good Clearance At The Stator Mount,

And better Stator Tooth Fitment,

Looks like it's time to do some Drilling...

You don't want that advance head rattling around on the limiter pin,
You don't want a HUGE screw holding the Stator on the advance plate,
So stay a little on the small side and sneak up on the hole sizes you need!

JeepHammer 03-01-2012 09:38 PM

This is the advance head with the stop pin hole drilled in it.
The fit is VERY snug, you don't want that advance head flopping around in the hole....

This is the advance head assembled on the shaft, springs and weights are no longer needed since ALL the spark timing is done in the computer.

This is the stator with the adjustment slot hole drilled and tapped, and a screw installed.
Just so happens, the Vacuum Advance screw I took out earlier was a self tapping screw, and it was the correct size/thread for the screw that held the Breaker Points down,
So I use that Vacuum Advance screw to tap the hole, then installed the breaker point screw to hold the Stator in place at one end.

I checked everything for clearance one more time,
Then I drilled the small screw hole for the Stator.

I used a 4x40 screw from Radio Shack,
I threaded the hole from the back side, sacrificing two or three screws to set the threads,
Then using another good screw from the top to hold the Stator in place.

Since this screw normally comes up right on the support ring in the housing, you will have to grind/field down the screw so it doesn't dig into that support ring under the advance plate.

This is the latest test fit, and everything is going fairly well so far,



Now, if you are going to run this as a 'Small Cap HEI' you will need to keep centrifugal advance and vacuum advance.

If you are going to run this as a 'Tach Signal' distributor for throttle body injection that DOES NOT have electronic spark control, You WILL NEED the vacuum advance.

IF you intend to run an Electronic Spark Timing (EST) Fuel Injection, Then the vacuum advance must go.... And here is how...

LEFT is the vacuum canister I just removed, see the scribe line scratched into it?
That is where I'm going to cut off the vacuum canister and keep the tab that goes in the distributor.

Just one of those bits of 'Trivia'...
RIGHT is a 'HEI Vacuum Advance', there is only ONE HEI Vacuum advance, for the large cap version.

The smaller ones like the one we are working with is a BREAKER POINT canister, not an HEI,
And there weren't any Vacuum Canisters on the small cap version of the HEI distributor since fuel injection had come along an taken over timing duties...

If you are going to order a new vacuum advance, make sure you get the 'Small Cap' version or it won't fit!
(Just one of those little 'Tech' things you won't find out anywhere else but an 'Ignition Geek' like me...)

If you are going to order a vacuum advance, for either a 'Small Cap HEI' build,
Or for a 'Tach Signal' Fuel Injection System,
Here is the best on the market, comes with tuning springs, adjustment 'Allen' wrench, An Advance LIMITER, which is a very good thing to have if you are going for fuel economy...

Crane Adjustable Vacuum Advance And Limiter Kit, Crane p/n 99601-1, about $39 from Summit Racing.


This is a 'Junk Yard' Build, so I'm going to saw off the Vacuum Advance I have and use the distributor mount for my Phasing control.
With a cut off Original Vacuum Advance, I'm exactly $22 into this for Reluctor, Stator, Screws and Dremel consumables, and I'm going to keep it as cheap as possible...

This is how you modify the tab to be adjustable for rotor phasing...

I leave the rod in place to fine tune Rotor Phasing before I put a bolt in the Vacuum Advance tab piece, makes for quick, easy location of the Stator Trigger point when I'm doing this set Up.

With the the permanent Bolt in place, it will look something like this...

This particular arrangement gives you something I haven't seen in any other conversion, PRECISE trigger position control once the distributor is installed...
I'll get into that more when I start with the chapter in rotor phasing and trigger position control.




If you are just looking to plug the hole, Or think sawing the one you have off is crass,

Personally, this is my favorite...
Plugs up the gap in the housing best, you might have to shave it down to plug up the hole in the housing so it makes a good, tight fit,
But it's a pain in the butt if you want to control rotor phasing with this one...


And this is the easiest to modify for rotor phasing...
But you will have to seal up the excess hole in the housing when you use this one...




There will be two basic modules you will be working with,
TOP The basic 4 Pin HEI Module, where the distributor is going to be controlling Ignition Advance,

BOTTOM, When the computer is going to be controlling Ignition Advance.

Since this is a 'Fuel Injection' thread, I'm going to cover full Computer Control (EST, ESC) modules first, and it's the most complicated.

The FI module heat sink will match up with the small housing, but the screw holes WILL NOT.
There is no terminal clearance, and you can't turn the module inward since harness connectors won't have clearance to connect to the module.

This means an adapter plate to clearance the module away from the housing, large enough to accommodate the screw mounting holes this module has.

That means screws holding the adapter plate to the housing, and screws for the module to mount, so this arrangement will take 4 screws total.

1-1/2" Hole Saw makes for a VERY clean notch in the adapter plate for extra clearance.

I used an angle grinder and some file work to fit this heat sink even tighter to the distributor underside...


Don't like to solder the wires to the module terminals,
Looking for that 'PERFECT' plug to adapt the Stator over to the FI Module?

Is $6 cheap enough?LINK: Rock Auto, Click This Line.

'90-'92 GM anything with a distributor and fuel injection...
Cut the wires off the stator that comes in and use the plug/pigtail for your module connection.



JeepHammer 03-01-2012 09:39 PM


To buy anything like it, it's going to run you between $300 -$500...
My cost, $20 For Reluctor, Stator, Nuts & Bolts,
You will need a small 3/8" or 1/2" thick piece of aluminum for the Module Adapter, can't see that costing more than $5...

If the moudule does not come with your FI system, the 4 Pin HEI style Module is $24 for the lifetime warranty version,

The lifetime warranty version of the HEI style module for Fuel Injection runs about $45...



You have some choices to make...
And this is putting your money where it should be put!
This low voltage trigger and module stuff isn't really difficult to work with,
but the correct HIGH VOLTAGE hardware will make or break your ignition!

The distributor cap is VERY important, and this will help you make up your mind about what will work best for YOUR application....
As you can tell, I use what works best for these applications, and for my money, NOTHING beats MSD distributor caps for a number of reasons.


BUT... With good plug terminals!

MSD p/n 84333, about $32 at Summit Racing.

Standard Rotor Only, MSD p/n 8467, around $9

I STRONGLY SUGGEST you buy a blow through proof, Phasable Rotor if you are running fuel injection!

MSD p/n 84211, $32 at Summit Racing.



Cap Only, MSD p/n 8433, About $30

Cap & Standard Rotor, MSD p/n 84335, about $30 at Summit Racing.

Rotor Only, MSD p/n 8467, Around $9,

I STRONGLY SUGGEST you buy a blow through proof, Phasable Rotor if you are running fuel injection!

MSD p/n 84211, $32 at Summit Racing.



MSD part number 8420, around $50 with phasable, blow proof rotor,
Cap center terminal is replaceable,
Rotor nose is replaceable,

The adapter will allow you to use common Ford V-8 caps in a pinch...
(and for Rotor Phasing when you have to cut a hole in a distributor cap, you REALLY don't want to cut up the MSD unit, so a discount store cap will fit right on...)

Spaces the terminals out further and uses a rotor that high energy ignitions can't blow though, making your spark energy getting the plug wires a slam dunk,

This cap also allows you to phase the cap, and the rotor,
And for Fuel Injection Systems that have timing control in the computer/module, this is a HUGE DEAL since 100% of spark advance shows up in rotor phasing with the spark plug terminals at the cap...
Where only Vacuum Advance shows up at the rotor with mechanical spark timing control!

It's what I'm running right now...
MSD Cap-A-Dapt, Ford Style Large Cap, MSD Phasable Rotor.
I wanted something I could pull a cap off the shelf if needed,
But the cap has replaceable center terminal, and it's over 10 Years old with no issues what so ever.
I have extra rotor noses,
The 'Cap-A-Dapt' is a one time buy, doesn't need to be replaced.

Phasable Rotor In Place,

Cap-A-Dapt Collar In Place To Mount The Larger Ford Style Cap...
(will accept off the shelf Ford V-8 Caps also)

MSD Verions Of Larger 'Ford' Style Cap In Place,

Another View Of Completed Cap Arrangement,
With the older style plug wire retainer on top,
The plug Wire Retainer attachment is built into the MSD caps now.


If you got this far, you spent some serious time and some REASONABLE money getting here,

Get a set of GOOD PLUG WIRES!
You spent all this time and money on this ignition, if you don't use some good plug wires, you are just shooting yourself in the foot!
Anywhere between 30% and 70% of your spark energy can be lost by using bad plug wires, and by installing plug wires incorrectly...

OFF THE SHELF, ready to install all but putting one end on the coil wire,
And that comes with a cutting/stripping gauge, crimping tool and instructions.

MSD p/n 35859, about $87 at Summit Racing.


You put your own cap terminals on once you cut to fit...

MSD p/n 31199, RED, set of 9 wires, about $88 Summit Racing.

MSD p/n 31193, BLACK, Set of 9 Wires, about $88 Summit Racing.


MSD p/n 8841, $13 set of 4, Summit Racing.

And keep them OFF METAL on the way to the plug.
Bundling wires, and draping them across metal is the fastest way to have your spark energy sucked away and to have cross fire (induction fire) problems!

So separate wires by at least 1/2" inch and keep the wires off metal on the way to the plugs.

JeepHammer 03-01-2012 11:19 PM


Here are some links to an old MSD service bulletin on rotor phasing,
Now, remember, with a mechanical advance distributor, only the VACUUM ADVANCE shows up at the rotor to plug terminal.

If you are running fuel injection 100% of the timing advance will show up at the rotor to plug terminal, so you MUST have a plan for correcting rotor phasing issues when you find them!

Link to page 1.

Link to page 2.

The SMALLER DIAMETER the distributor cap you choose, the more likely you are to have Rotor Phasing issues...
So just be aware of this,

And just for the record,

Here is a link to MSD's latest version of Rotor Phasing information, .pdf format.

Click On This Line For Link.


The rotor is DIRECTLY LINKED, In lock step, with the engine.

WITH A FIXED CAP ON THE DISTRIBUTOR BODY, The plug wire terminals move in lock step with distributor body.


Most are ZERO DEGREES (0), the computer is looking for a TOP DEAD CENTER reference signal for each cylinder, and the closer you get to that 'Perfect' TDC mark, the better the engine is going to run.

By making the TRIGGER (Stator) adjustable, you have the ability to give the computer a PRECISE TDC signal, While still being able to adjust the rotor phasing by turning the distributor.

I've not seen this method used anywhere else, but I'm sure now that I've posted it, it will pop up all over the place, like the other upgrades I've done with ignitions, carbs, wiring and drive trains...


Since most ESC or EST Computers/Ignition Modules will throw around 40-45 of ignition advance,
You will need to have the rotor compensated for that advance, since every bit of it will show up at the Rotor/Cap Terminal positioning.

Distributor turns at HALF SPEED the engine, so the rotor needs to start out about 20 to 22.5 degrees to the 'Retarded' side, and it will 'Sweep' the terminal to 20 to 22.5 degrees from center line of the distributor to the 'Advance' side.

When you use an 'Off The Shelf' or other type of 'Lock Down' for the vacuum advance, you simply directly mechanically link the trigger to the housing, so turning the housing changes the timing, and you can't use housing rotation to 'Fine Tune' the rotor phasing...

The old Vacuum Advance 'Slot' in the arm gives you somewhere between 10-15 adjustment, and you can use that to your advantage when fine tuning the Rotor Phasing/Trigger (Stator) Position before you lock down the Trigger (Stator),
If you have to move the housing to adjust Rotor Phasing, they you simply move the Trigger (Stator) so it's back in the correct position for a 'TDC' Signal again.

Very simple concept, which I've tried to explain to some of the guys on forums with 'Fuel Injection' sections, but they simply can't grasp the concept...
So now you are ahead of the 'Curve' (pun intended! :))... AGAIN!



There is more than one way to do this, but since I won't let an ignition out of here without Phasing the rotor correctly, this is some of my test gear for checking Rotor Phasing...


There are 13 teeth on your AMC distributor gear, that means no 'Center', there IS a 'Front' and a 'Back' to the gear!
Get the gear back on in the correct position!


Now, to get you started...

Install distributor into engine with rotor pointing in the correct direction for #1...

Get the housing lined up with the rotor pointing slightly PAST #1 (in clockwise rotation) so the rotor will 'Sweep' the #1 terminal as advance comes 'In'...

The Rotor is in the 'Retarded' or 'Zero Advance' position.

Then set your Stator (Trigger) via the adjustable vacuum advance mechanism you made out of the old vacuum advance arm until the 'Tooth' in the stator lines up with the closest point on the reluctor.

This will get you VERY close to EXACTLY the correct 'Zero' or TDC trigger signal the computer needs,
And still allows you to control every aspect of Rotor Phasing (Turning the housing/cap and/or Phasable Rotor for fine tuning),

Stator 'Zero' (Old Vacuum advance), Is something you can't buy on the market,
(Can't buy YET, I'm sure someone will start making them now that the engineering has been done for them! :mad:)

VERY simple to do and makes your distributor MUCH MORE PRECISELY TUNED than the 'Off The Shelf' units you pay $300-$500 for...


THE 'SPIDER', test cap, test rotor, testing plug wires for any V-8 running a 'Ford' distributor cap.
Notice the Firing Order for various engines is written on the cap, along with rotation for each engine,
And the plug wires are a mess (8 Spider Legs) but long enough to reach every cylinder on any V-8 engine...

The distributor cap I cut the "Window" into so I can watch the rotor in action while the ignition advances and retards during operation...
CHEAP CAP since you are going to cut a giant hole in it!

I put a stripe of NON-Conductive paint on the rotor center line so I can see exact center line better with the timing light...


This is pretty typical for 'Vacuum Advance' misalignment.
With ESC or EST you will show DOUBLE this amount of rotor 'Sweep' since all the advance will show up at the rotor, and that should tell you the rotor will be well on it's way to the WRONG terminal at full advance!

With CORRECTED Rotor Phasing, you will wind up with something like this with EST or ESC running the show...


Now, most people don't think the increased cap diameter is a big deal...

Here are two things to consider,

1. Distance between terminals.
The smaller the cap, the closer the terminals.
Much larger chance for spark energy to go the wrong way, ESPECIALLY if the Rotor Phasing is off and the Rotor is closer to the WRONG terminal when the ignition fires...

2. The small diameter caps use a SMALL ROTOR NOSE at the plug terminals.
The 'HEI' and 'Ford' large caps use a WIDE rotor nose, to keep the rotor firing the Correct terminal,
See the width of this rotor nose at the Plug Terminals?

Now, have a look at the width of the Rotor Nose on the small cap Rotor...

With a 'Small Cap' you have to be MUCH more precise with Spark Energy Control or you WILL fire the wrong cylinder!
So Rotor Phasing is a MUST to keep the Spark Energy from firing the wrong cylinder!

This little ADJUSTABLE Stator controller, which cost you a Screw and a couple of small nuts,
Will allow you to set your Rotor Phasing PRECISELY...
And SPECIFICALLY FOR YOUR ENGINE, instead of a 'One Size Fits NOTHING' lock down you can't adjust...

And I can't drill this into the heads of the 'Fuel Injection Experts' on the other forums...
They argue against large cap spacing, tall rotors, and a bunch of other things also, which makes no sense to me...


Better pictures when the cap/rotor comes in...

CSP 03-02-2012 08:07 AM

Good stuff (though the module wiring diagram seems to be missing an IMG tag at the end). I've seen people do the same distributor conversion with the 4-pin HEI module for non-EFI applications or EFI applications like Howell where the spark isn't controlled by the ECM.

Can you even use the seven or eight pin modules if your EFI does not have spark control? I don't believe you can.

JeepHammer 03-02-2012 03:44 PM

HEI Trigger in the small base circle distributor?
It can be done, but you have to do a little aluminum cutting...

Or how about a Ford Trigger version?

papa355 03-02-2012 04:37 PM

damn JH, you must be reading my mind. I was going to ask you the other day about what distributor to run on a 304, for TBI conversion.

A Co-worker just gave me a complete TBI set up off of a 87 Chevy 3500, with a 350 cu in. Throttle body, computer, wiring harness,coil and the distributor. He took it all off and went back to carb set up. It was running but would not idle down, correctly. Is that a TBI problem, you think?

Can I adapt the distributor he gave me to work in a 304? Is this the right TBI set up to use? I have an old points GM distributor, like you are building also.

Sorry to hijack, I been searching this the last couple of nights, and reading those post. But since you started this thread, I thought it kinda went with it.

CSP 03-02-2012 04:44 PM


Originally Posted by papa355 (Post 13163639)
A Co-worker just gave me a complete TBI set up off of a 87 Chevy 3500, with a 350 cu in. Throttle body, computer, wiring harness,coil and the distributor. He took it all off and went back to carb set up. It was running but would not idle down, correctly. Is that a TBI problem, you think?

The problem could be a number of things. Something as simple as a vacuum leak can make it idle too high.


Can I adapt the distributor he gave me to work in a 304? Is this the right TBI set up to use? I have an old points GM distributor, like you are building also.
The Chevy distributor can't be adapted to the 304 without a ton of modification. You would almost be starting from scratch. A Caddy one can with less mods, but there are better options. Any electronic distributor can be easily modified to work with TBI. I've modified several '78-91 AMC Duraspark distributors, which takes little to no modification. It's a matter of disabling the vacuum and mechanical advance and you're done. If you have an AMC version of the GM points distributor you can do the mods JH is showing here.

Read the Fuel Injection FAQ sticky thread at the top of this forum link for starters. There are dizzy mods shown there too.

mopar346 03-02-2012 06:21 PM

Very educational write up, it is rare to have the abilities and be able to amply put it in a useful thread.

I am running a DUI with a carb and am happy with the set up although it is uncomfortably close the power steering, so I can see the need for what you are doing. My question is more academic or out of curiousity. Wha tis your opinion of a Unilite under cap conversion. I have run unilites, both conversion and complete distributors for going on 30 years now and really like them.

JeepHammer 03-02-2012 07:29 PM

I don't like Mallory in general and Unilite in particular, they have left me walking too many times.


I also have HEI electronic trigger versions of this,
And I have Ford Trigger versions of this for this very distributor,

But you have NEVER SEE THE WORDS "LATHE CUT" OR "MILLING MACHINE" with this version shown...

I may do the others some time and post them, but this is a NO MACHINING, nothing you can't do with hand tools,
Drill, Dremel tool, ect.

I thought that was Important for this first pass on things... Not everyone had a head mill or lathe handy...

You do know this very distributor conversion runs about $300 when you buy it, and that's usually without plug wires, cap, rotor or module...

mopar346 03-02-2012 07:36 PM

Fair enough.

papa355 03-02-2012 08:16 PM


Originally Posted by CSP (Post 13163679)
The problem could be a number of things. Something as simple as a vacuum leak can make it idle too high.

The Chevy distributor can't be adapted to the 304 without a ton of modification. You would almost be starting from scratch. A Caddy one can with less mods, but there are better options. Any electronic distributor can be easily modified to work with TBI. I've modified several '78-91 AMC Duraspark distributors, which takes little to no modification. It's a matter of disabling the vacuum and mechanical advance and you're done. If you have an AMC version of the GM points distributor you can do the mods JH is showing here.

Read the Fuel Injection FAQ sticky thread at the top of this forum link for starters. There are dizzy mods shown there too.

A vacuum leak is the first thing I told him to check for. But he was dead set on converting back to carb and HEI, and once he said I could have all the TBI stuff( for free.) I agreed 100% that he should get rid of all that crappy ole TBI stuff ;). He is pretty diehard carb/&hand choke and old school car kinda guy. He drives a '68 chevy truck, '60 (something)Falcon, about a '88 YJ, now the '87 1 ton (now carbed). He hates anything with a computer. I knew that fuel injection was headed my way when he bought that But his wife drives a 2011 Hemi 1500 Ram.:laugh:

I actually did look thru that link you posted. I saw it on another thread on this site, the other night when I was searching TBI upgrades.(I am sure you posted it then). I will gather up all the stuff I need and maybe tackle this mod next winter.

Thanks for the reply.

and great write up JH, I really am reading this stuff :), good stuff man.

Jon In Tucson 03-02-2012 08:53 PM

If the TBI ecm is the 7747 version you are golden for the conversion. I did my 258 I6 with all the parts from a '90 Astro van. Did you get the ALDL connector from inside the cab? As you tune and log data it sure helps. Also you can stop in any Autozone and have them read a code for you, if you're are out and about... God bless.
Jon in Tucson

Zorty 03-06-2012 03:21 PM

Well I have been reading the almighty publications that the great zen-master Jeephammer has posted over time as I slowly plan my upgrades. I have a 304 dropped into an '83 CJ7 from a PO or three ago. Ignorantly I just assumed that the engine was from the '78-'90 range with the Motorcraft style distributor, even though I never saw any Duraspark module (I have no idea why I would assume this), so I've been following the Teamrush recommendations for the 304 from post #2 of Jeephammer's "Ignition Upgrade..." thread. I broke down and bought all the necessary parts to do the complete swap, from new plugs out through the MSD 8414 Cap-a-dapt, and even threw in a MSD 6A CDI box as well that I practically stole off craigslist. Then, as I rebuilt my Holley carb this last weekend, I started looking at the distributor and wondered why I didn't have the three wire orange/pink/black plug coming out from it- only a single black wire. I pulled the cap and low and behold, found that I have a breaker point style distributor.

Now, after stumbling onto this newer thread that applies to the distributor currently on my engine, I'm facing a new question that I wanted to post in this forum to capture. I have no fuel injection at the moment, simply a Holley 4 barrel carb, with a breaker point ignition and MSD blaster 2 coil. After my last stint with hills offroading and having the carb/engine die every climb attempt, fuel injection (or even propane) has crossed my mind, but is just not in the immediate plans or budget. I drive this Jeep as much as I can, so it sees more street time than trail time (sadly). My question is, should I try this conversion of my old breaker points distributor, or should I head up to the ol' parts store and grab a reman Motorcraft distributor to replace the breaker point dizzy? I would still like to incorporate the MSD 6A CDI box, as it sounds like that's generally the best option, and I already have it. Is one more cost effective than the other? More reliable or better performance? Would one "future-proof" me to be able to run the carb now, but have an easier time adding fuel injection down the road if I decide to?

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