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Discussion Starter · #1 ·
I didn't know much about the 258 I-6 until recently. I do know a considerable amount about ignitions. I put the information and know how together to create this document.

Ignition Up Grade For The Jeep 258 Cubic Inch Displacement, Inline 6 Cylinder Engine

The Jeep 258 CID I-6 from 1978 to 1990 are eligible for this upgrade.
The 258 I-6 from '78 to '90 used the same Motorcraft distributor for all variations.
(If you have a 258 CID I-6, 1977 or older, I urge you to see below*)

The 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 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.

Stock Parts To Replace: (stock jeep components)
Distributor Cap, Rotor, Plug Wires, Distributor Advance Springs, Ignition Coil.

What To Use For Replacement UPGRADE:
FROM: For A 1981 Ford F-150 Pick Up Truck With A 300 CID I-6 Engine.
Distributor Cap Base,
Distributor Cap,
Rotor,
Spark Plug Wires,
Ignition Coil,

Distributor Centrifugal Advance Springs;
FROM: Aftermarket Supplier.
Mr. Gasket P/N 925D

This upgrade will bring your Jeep ignition system into the mainstream 70's technology.

HIGH PERFORMANCE UPGRADES:
Once the cap, rotor and plug wires have been upgraded, then you can use some 80's technology in the form of the THICK FILM INTEGRATED (TFI) ignition coil.
The TFI coil is Motorcraft's answer to the GM HEI coil, and out preforms the common GM HEI coil by about 1-1/2 times.
(yes, that's correct, the TFI coil stomps the GM HEI coil)
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 coil from a '84 Ford F-150 Pickup with a V-8 engine (WITH-EEC). The coil runs about $20 in discount stores. GP Sorensen P/N GC407S. AC Delco P/N F503Z.
Borg-Warner P/N E-92,
Standard Ignition P/N FD479,
Niehoff P/N FF-179

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 D.U.I. ignitions and all JACOBS ignitions.


Multiple Spark Discharge (A CDI module upgrade) gives vastly superior ignition energy on all counts. Spark Duration, Spark Voltage, and Spark Amperage. In all areas the MSD Capacitive discharge module driven ignition will out preform the Inductive ignitions in all areas, from 100 to 1,000%.
MSD is the biggest and best bang for your bucks.

The MSD 6 series units are compatible with all Motorcraft distributors and ignition coils.
The MSD 6A unit is enough for most stock or lightly modified applications. Around $135.
The MSD 6AL unit is the Cadillac of the 6 series with compatibility with all of the usual MSD timing devices, and it has a built in Soft Touch Rev Control. Around $175.
The MSD 6 Off Road, This unit is built like a tank. Epoxy sealed for water resistance and equipped with Weather Pack water proof connectors. Around $215.

Use Wiring Adaptor P/N 8869 to connect the Motorcraft distributor connector to the MSD 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.

*1977 And Older 258 CID I-6 With The Delco Breaker Points Style Distributor.
You have three choices,
1. Up Grade to the Motorcraft distributor & DuraSpark ignition module, and add the upgrades described above for the Motorcraft distributor.
2. Use an electronic ignition conversion kit for the Delco distributor, and use the DuraSpark or MSD ignition modules, but you will have to go to the aftermarket for adequate distributor caps & rotors.
3. Use a MSD ignition module that will work with breaker points. You will still have to go the aftermarket for adequate distributor caps & rotors.


So many cats, So few recipes....
 
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Again Aaron, thank you! I'm not looking to make a fire breathing, mega-horse-power beast out of my 258,just a smooth, dependable, sweet running happy camper. It ran great in fair weather, but it always suffered on those 35 degree, rainy, foggy morning starts. It sounded more like a two cylinder John Deere for the first 15 minutes. Not fun to try and go plow snow with! One morning I swapped the month-old cap and wires for the old grungy ones I had removed-BINGO!-ran fine. Somewhere, the stock cap and wires just don't like cold, icky mornings!
BTW-What would you recommend for plugs and gap settings?

Grant
60 CJ5
80 CJ5
 

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Nice post, thanks for the information. Are you familiar with the Jacobs Energy Coil?. I wanted an easy, fairly inexpensive upgrade for the ignition on my 90 258. I went with the Jacobs Energy Coil, Jacobs plug wires and Champion Truck plugs gapped to .050. I didn't have any major problems before upgrading, I was just tweaking. It does start much better now. What is your opinion of this setup? I picked up a lot of ignition noise on the radio after this upgrade and was wondering what the best way is to get rid of it.

There are a lot of different opinions on spark plug gapping, indexing and regular versus platinum. I bought a set of the new Bosch Platinum 4 because they solve the indexing problem, but have since read criticism of platinum plugs. What do you recommend for spark plugs?

jerry
 
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Arron,

IS the TFI coil a good upgrade for the '77 304? You didn't mention it as an upgrade in your previous answer. You had also mentioned that the bigger cap has the sparkplug style connectors on the towers instead of the stock jeep type, shouldn't I get a different cap that has that style connector also? or does it not matter as much? Just curious.

Thnx

Florida Mud CJ-5
'77 RB304, t-150 D20 4" 35" swampers
 

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Discussion Starter · #5 ·
I'm not going to get into the spark plug 'HE Said-- SHE Said'....
The manufacturer of the specialty plugs all make claims I, or anyone I know, have been able to duplicate. I don't think anyone ever will.
I remember one company that claimed their 'V' split ground electrode plug was going to add 6 more MPG and 35 to 45 more horse power. (45 HP would double the output of a Yugo...)
One of the hot rod magazines tried them in a fresh engine rebuild they had just completed. The plugs added a grand total of 2 horsepower.
When the plugs they broke the engine in with were replaced with a new set of common plugs, they showed a 11 horse power gain.
I attribute the 2 horse power gain to the engine tolerances getting looser during the break in cycle, or to mechanical variance in the dyno. It wasn't a large enough gain to trust.
The 11 horsepower gain was probably due to a set of eight working plugs, and the furthering of the break in process.

I use mostly Autolite plugs. I have less trouble with them, and have a few less failures out of the box.
I also had pretty good experience with Nippon-Denso (spelling) spark plugs.
I used the N-D, so called, 'U' Groove spark plugs in my Harleys and they seem to do a little better than most plugs. At about $0.99 each, I could just throw them away when out of town. (otherwise I clean them till there is nothing left of them)
(Accel packages the same plug for bikes at about $5 each)



If you Pry down on the center electrode to gap the plug, and you stand a 50/50 chance of scraping a plug that was good.
Grab on to the ground electrode with a pair of needle nose pliers to bend it. Don't pry on the center electrode. If you do, you stand a very good chance of breaking the porcelain, slipping the electrode in the porcelain, breaking the carbon pile (the resistor in resistor plugs), or a half a dozen other things can go wrong.
If you ever drop a plug on a hard surface, just throw it away.
Spark plugs are very delicate, and easily damaged.

All I know is we gap plugs, and test plugs on the bench before we even install them.
Normally one out of ten is scrap from the factory. That is all brands.

The only way I know of to test plugs correctly is to give them a full scale, full power bench test, and see which one takes more voltage to fire on the scope.
Not something a home tune up man can do... And not something the average custom shop is set up to do.

As far as spark plug gap goes:
If you run a stock canister type coil, stay around 0.035".
If you run an HEI coil or TFI coil or any of the high out put aftermarket coils, 0.045".
If you have an MSD module or other CDI ignition module, 0.045" to 0.065".
There doesn't seem to be much of a gain after 0.065" gap.


Sorry I couldn't help.

So many cats, So few recipes....
 

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Discussion Starter · #6 ·
*JERRY* asked,
*Are you familiar with the Jacobs Energy Coil?. I wanted an easy, fairly inexpensive upgrade for the ignition on my 90 258.*

Do what I mentioned in the article with the Cap, Rotor, Plug Wire, and TFI Coil with the Dura Spark module and you should achieve what you asked about.
---------------------------------------------------
I don't like bashing any person or business unless I just have to. You ask a direct question, and Jacobs has done nothing to me, so I'm going to stay with the facts here.
All of Jacobs products are INDUCTIVE ignition products. They are brightly painted with flashy stickers, and a price to make you think you are getting the best, but the truth is all Jacobs products are only slightly better than the stock units your vehicle came with, and in some cases, not as dependable.
Please don't make me pursue this line of thought any farther, All of the people that work at Jacobs have mouths to feed.
----------------------------------------------------
*I went with the Jacobs Energy Coil, Jacobs plug wires and Champion Truck plugs gapped to .050. I didn't have any major problems before upgrading, I was just tweaking. It does start much better now. What is your opinion of this setup?*

If you like it, and it works for you, and it's what you wanted, I LOVE IT! Couldn't be better!
----------------------------------------------------
*I picked up a lot of ignition noise on the radio after this upgrade and was wondering what the best way is to get rid of it.*

The noise is probably coming from RF noise produced by the unshielded coil and the plug wires.
You might using a sheet metal cover over the distributor and ignition coil. Make sure it's grounded well. (Like the Corvette had for several years)
Or try the factory Cap, Rotor, Plug Wires and TFI Coil I recommended in the article. I would only do this as a last resort though, because of the expense of your new stuff, and the added expense of the Factory Ford stuff.
---------------------------------------------------
*There are a lot of different opinions on spark plug gapping, indexing and regular versus platinum. I bought a set of the new Bosch Platinum 4 because they solve the indexing problem, but have since read criticism of platinum plugs. What do you recommend for spark plugs?*

Gapping is easy, use the maximum amount of gap you can and have everything work correctly. For the set up you described, around 0.045" should be about correct.

Platinum is a wonderful, noble metal! I can see no reason to waste it in spark plugs though. Silver or copper if they could with stand the heat would make much better choices for conductors. Steel is just fine for the spark plug the way it is designed right now. (

Current spark plug design dates back to the 1890's. It was first designed to be an air gap for the first AM radio experiments.
The current 'Gapless' (a gapless spark plug is an oxymoron) spark plugs use four ground electrodes at 90 intervals around the center electrode. This particular design dates back to WWI aircraft. The air gap, and subsequent spark, lays parallel to the direction of the flame front in the cylinder.
The Spark needs to be perpendicular to the flame front travel to properly start the flame front. That is the theory behind the 6 to 8% power loss and increase in hydrocarbon emissions when we use Bosch gapless plugs.

The ground electrode doesn't need to be indexed in stock engines. It doesn't produce enough of an impedance at low RPM to have any real effect on burn times or flame front rates.
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*Fl. Mud CJ-5* Asked,
*IS the TFI coil a good upgrade for the '77 304? You didn't mention it as an upgrade in your previous answer.*

YES! It is a bolt on upgrade for anyone with a DuraSpark module. It's funny looking compared to what the canister coil looks like, but works great with no other modifications besides the cap, rotor and plug wire one outlined earlier.
The Ford TFI coil out preforms the GM HEI on all important issues by 1-1/2 times!
It's canned lighting for the DuraSpark equipped Jeeps!
-------------------------------------------
Ford had a problem with the TFI coils until 1996. The design has been upgraded, and I am told by every aftermarket distributor I spoke with the replacement coils are ALL upgraded.
-------------------------------------------
*You had also mentioned that the bigger cap has the sparkplug style connectors on the towers instead of the stock jeep type, shouldn't I get a different cap that has that style connector also? or does it not matter as much? Just curious.*

It matters a bunch! The terminals on the wide Ford cap are designed to work with High Ignition Energy. So are the plug wires. The ford cap end boots on the plug wires have longer sealing surfaces to keep crud out, and voltage in.
If you use the TFI coil on the small jeep cap, you will cross fire to beat the band, Use the larger cap to separate the terminals, and the taller rotor to keep the spark from jumping to ground on the distributor shaft.
--------------------------------------------

BTW, I will be completing a comprehensive V-8 article in the next day or so, and I will post it here...

So many cats, So few recipes....
 
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Team Rush, your post suggests that the MSD6A unit would be a good upgrade, useable with the Motorcraft distributor. The only catalog I have showing the MSD system is from 4WD Hardware and instead of the $135 or so you talk about it lists only the MSD Off Road for $269.00

Where might I shop for the MSD system you show for $135? Let me be certain I have it right, I can use my stock distributor (1980 258 - stock) but would be better off with the cap, rotor, plug wires adv springs and coil from a 1981 Ford 300ci engine? You also mention the cap base? That is not the distributor body? Then I would need the p/n 8869 (is that a MSD part number?) Thanks

 
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Summit Racing has the MSD system for $135 http://www.summitracing.com. The distributor cap base is not the dist. body. Ford used a two piece cap and yes, use the parts from a '81 300. The wiring harness part number is a MSD part number and Summit carries them. They might not be in the catalog, but they carry a lot of things that aren't in their catalog. Just ask the salesperson on the phone.
 

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Discussion Starter · #9 ·
*John* asked,
Question #1
*Team Rush, your post suggests that the MSD6A unit would be a good upgrade, useable with the Motorcraft distributor. The only catalog I have showing the MSD system is from 4WD Hardware and instead of the $135 or so you talk about it lists only the MSD Off Road for $269.00*

Question #2
*Where might I shop for the MSD system you show for $135?*

Question #3
*I can usemy stock distributor (1980 258 - stock) but would be better off with the cap, rotor, plug wires adv springs and coil from a 1981 Ford 300ci engine? You also mention the cap base? That is not the distributor body?*

Question #4
*Then I would need the p/n 8869 (is that a MSD part number?)*
--------------------------------

AND SNOWTOW ANSWERED...

*Snowtow*
*Summit Racing has the MSD system for $135 http://www.summitracing.com.
The distributor cap base is not the dist. body.
Ford used a two piece cap and yes, use the parts from a '81 300.
The wiring harness part number is a MSD part number and Summit carries them. They might not be in the catalog, but they carry a lot of things that aren't in their catalog. Just ask the salesperson on the phone.*
----------------------------------

AND HE IS CORRECT ON ALL COUNTS!!
Good job Snowtow!

----------------------------------

Summit uses MSD's part numbers, the only difference is Summit puts an MSD in front of the part number.

Here is the entire rundown on applicable units...
The MSD 6 series units are compatible with all Motorcraft distributors and ignition coils.
The MSD 6A, P/N 6200, unit is enough for most stock or lightly modified applications. Around $135.
The MSD 6AL, P/N 6420, unit is the Cadillac of the 6 series with compatibility with all of the usual MSD timing devices, and it has a built in Soft Touch Rev Control. Around $175.
The MSD 6 Off Road, This unit is built like a tank. Epoxy sealed for water resistance and equipped with Weather Pack water proof connectors. Around $215.
The MSD 6M-2, P/N 6460, is completely water sealed, and was intended for offshore power boating. This is the hot ticket for the guys doing water racing or deep water fording. It comes with both sides of Weather Pack connectors for sealed connections also.

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.
---------------------------------
Don't forget the TFI coil. That factory coil really kicks butt!
MSD has a version of the TFI coil, P/N 8227 that is even hotter yet! And it can be used with the factory ignition without the MSD module.... Just food for thought.....
---------------------------------

It's good to see so many people paying attention and interested in the upgrade. Makes it seem like my time wasn't wasted.

Good luck guys! Aaron.

I'm desperately trying to figure out why kamikaze pilots wore helmets...
 
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Hey TeamRush, are you pulling my leg? The TFI conversion is better for my Jeep then the HEI? And I don't need to change out the distributor and jerk around with the timing? Sorry to go over old ground, but this was a conversion I'm planning to do until I read your post. I was nervous about the distributor part of the HEI.

'83 CJ7 258 i6 31x10.5 3in. lift? /wwwthreads_images/icons/cool.gif
 
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Jeep Head,
Do a search on TeamRush and look at some of the posts from last week. Aaron gives a TON of information on how the Motorcraft setup is far superior to the HEI (not that the HEI is necessarily bad). You will have to pull the distributor to change the mechanical advance springs. I found out about the compatibility of the Ford stuff with the Jeep stuff a couple of years ago and pulled my Prestolite distributor and replaced it with Motorcraft like TeamRush has described. The drivability problems that I had been experiencing were gone. Now I am thinking about adding the MSD box to get CDI (capacative discharge). My snowmobiles use CDI ignition and reliably run between 9,000 and 10,000 RPM with no ignition problems whatsoever. Now I am going to tinker around with Aaron's ideas for the small block Chevy on my '68 Camaro. It will pull 7,500 RPM with points (modified) so I am anxious to see how it runs with electronic ignition and CDI!

 
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Thanks for the info, I'll do a search. Is there any sites that have detailed instructions (preferably with pictures)?

'83 CJ7 258 i6 31x10.5 3in. lift? /wwwthreads_images/icons/cool.gif
 

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Discussion Starter · #13 ·
The Motorcraft TFI coil is a full 10 years ahead of the GM HEI coil in technology.
Twenty years actually, Motorcraft redesigned it again in 96, so it's about 20 years ahead of the GM HEI now.
GM never redesigned the in cap HEI coil, from it's inception in 1974 to present.
The TFI coil made the scene in 1982 in cars and 1983 in trucks. It was redesigned in 96 to correct a magnetic field problem and came out of the redesign even stronger than ever.
I am told by an engineer at Ford's SVO Group that all of the major manufacturers have incorporated the redesign into all replacement coils, so the one you buy at auto-jerks should be the redesigned version.

If you get one off of a 95 or older vehicle, it will work just fine, but some of them interfered with stuff like radios, fuel injection and stuff like that.

FYI, The Ford SVO guys get their TFI coils from the same manufacturer that makes MSD's coils. They are one in the same. If it's good enough for SVO and MSD, I'm sure I'm going to be happy with it.... (MSD P/N 8227)
---------------------------------
In case the GM HEI advocates are listening.... I just wanted to drive another nail the he GM HEI conversion coffin...
GM doesn't use the Coil-In-Cap design anymore. They use a two connector remote coil. ==== Remote coil, you know, like the Motorcraft ignition system....====
The new GM two connector coils have IDENTICAL OUTPUT in duration and voltage to the TFI coils.
Looks like Ford had the hot ticket around '82 and GM is just now catching up...
GM knows a good thing when they see it, so they copied it! Turn ratios are the same, output is the same, duration is the same, inductance the same, primary resistance the same.... Looks like GM just had Motorcraft do their R&D and 15 years of field testing for them.
--------------------------------
Is that what you wanted to know?

I don't have anything on a web site yet, and I can't get Off-Road.com to even e-mail me back about posting the article with pictures I already have done.
We've been kicking around the idea of posting it on our company web site with it's own domain name, but talk is as far as we have gone so far...
I don't do web sites, and our graphics girl just got fired, and the big computer dog gets about $100 an hour to do stuff...
I like you guys, but not $2,000 to $2,500 worth!

See ya, Aaron.

I'm desperately trying to figure out why kamikaze pilots wore helmets...
 
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damn aaron, you just keep givin away all of us ford guys secrets. /wwwthreads_images/icons/smile.gif

this is why you do not see a lot of aftermarket ford distributors. we have just quietly been doing our own thing, and not been bothered by big ignition changes (saves money for other cool stuff).

if you are looking for a site to post your info try 4x4play.com. this is a new and quick growing site based in the nw that would love to add stuff to their tech pages. i met with them at the pnw4wda winter convention and they seemed really receptive to outside input. might be worth a try.

dan

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

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I think that the whole concept of the distribuator is poor. As soon as I can afford two more coils, it's d.i.s. with coil on plug. Forget about the plug wires, look under the hood of a y2k 4.0l!

 

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Discussion Starter · #16 ·
It may be a poor idea to you, but not everybody wants to throw $1,500 to $2,000 at a carbureted engine for a distributor less ignition.
I could tell them how to go crank trigger with four pickups, four modules and four coils with no distributor, but the performance gains on a relatively low performance engine would be wasted, just like the money for the hardware.
Just like the money for the system you are talking about.
A total waste performance and money wise, but if you really want it, I'm behind you 1,000% !
If you really want the trickiest of all ignitions on the BBS, send me $3,000 and I'll build you one that not even the best garage in town can figure out if something goes wrong...
It'll be COOL though!

I'm desperately trying to figure out why kamikaze pilots wore helmets...
 

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The distributor cap base that you mentioned, is that something that can be picked up at the local Manny, Moe, & Jack Parts Emporium or will I need to make a trip to the local U-pull it?

 
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any "good" parts house will have these.

dan
NECESSITY IS THE MOTHER OF INVENTION
/wwwthreads_images/icons/cool.gifLET IT SNOW/wwwthreads_images/icons/cool.gif
 

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Discussion Starter · #19 ·
THE QUESTION:
*The distributor cap base that you mentioned, is that something that can be picked up at the local Manny, Moe, & Jack Parts Emporium or will I need to make a trip to the local U-pull it?*

Black Jack is correct.
Every one of the chain discount houses will have them in stock, so will every mom & pop parts store worth it's weight in sand.
Ford used them from 1975 to 1989 in one vehicle or another, and from 1976 to 1984 in all V-8 vehicles.
It's worth the extra money for the premium grade Cap Base, or to get one from Ford or MSD because this is a one time purchase. Once the Cap Base is in place, it stays in place, it's not a wear part, so it doesen't get replaced during tune-ups. It stays for the duration, and unless you damage it working on something, it will last the life of the vehicle.
The premium version over the discount version is only about $3 to $5 extra.

I'm desperately trying to figure out why kamikaze pilots wore helmets...
 

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Thanks for the info. I picked up all the parts this evening. Now, would you guys please stop posting all these performance "secrets". Every time you do it costs me double. Once for the jeep I am restoring, and once again for the jeep my wife is driving. If she sees me getting something for mine, wellll, hers has got to have it too. I'm going broke....

 
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