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Frequently Asked Questions (FAQ)

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I am going to try and compile a list of these FAQ's... Please if you have a link and question that is always thrown around... please post so I can put this together...

1. What Headers will fit a Stock K-member?
We have had many use the JBA mid-length headers with 3" collector with many aftermarket K-members and even stock. We also have our JBA shorties and they will work 100% but they have a 2.25" collector so you have a smaller outlet on the headers. Check out the mid-length images below and if you need any additional information please let me know.
6632S for the 2v Motor
http://images.pertronix.com/Exhaust Products/JBA Exhaust/6632S.jpg
6635S for the 4v motors.
http://images.pertronix.com/Exhaust Products/JBA Exhaust/6635S.jpg
909-599-5955 x 1402
Dustin - JBA Headers
2. What Headers will fit a Tubular K-member?
We have had many use the JBA mid-length headers with 3" collector with many aftermarket K-members and even stock. We also have our JBA shorties and they will work 100% but they have a 2.25" collector so you have a smaller outlet on the headers. Check out the mid-length images below and if you need any additional information please let me know.
6632S for the 2v Motor
http://images.pertronix.com/Exhaust Products/JBA Exhaust/6632S.jpg
6635S for the 4v motors.
http://images.pertronix.com/Exhaust Products/JBA Exhaust/6635S.jpg
909-599-5955 x 1402
Dustin - JBA Headers
3. Can I use a 1996-1998 GT Wiring Harness for a 4V engine?
(Can I use my GT computer and harness to start the car as of right now, (aside from the IMRCs, and PATS which are wired open and disabled) the car should fire and run off of the gt programming until i can get it to my local tuner to accomidate for the 24LB injectors and so forth?)

The bulk of this era ECU are of the CDAN4 family. They are all literally the same physical EEC, but with different calibrations in them.

So, to answer your questions more directly: The GT ECU will work great, the fuel trims will be quite a ways out to start, but it will run and drive. If you want to, you can add in the wiring for the IMRC's to the GT harness. It's up to you. The GT EEC definitely has the abitlity to control IMRC's. Your tuner may modify the GT calibration or use one of the cobra calibrations or a combination of both. Do you know if he will be chipping the ecu or using a flash programer?
Mod fox's car is pretty much identical to your setup. Lincoln motor with IMRC wired open and a GT harness and ecu. In his case I simply modified the GT calibration.
CCRM Question

4. '88 dash to the Modular wiring.
FuturaGuy said:
Connectors C213, C216, and C259 all connect to their counterparts on the Modular computer harness. The Modular harness also has a fourth connector, C202, which is a round white connector with provision for 4 pins. In non-California cars, there is only one pin, circuit 29, a yellow and white wire that connects to the gas gauge. Not having the mate to C202, I ran the yellow and white wire to a vacant hole in C216.

On the other end of the harness, I used an 11-pin connector (with 5 blanks) that I labelled C1108. The two halves of the connector came from the damaged harnesses from the donor car, and was the connector (C108) behind the right head light that connects the computer harness and the fuse box harness. The eleven wires shown connected thru C1108, with one exception, come from the bundle in the '88 dash that used to go thru the firewall next to the steering column. C135 mates to the green 8-pin connector from the dash and goes behind the passenger kick panel to feed the old computer. C245 goes to another small jumper harness that connects to C243 and C244 in the dash. Those normally connect to a module used only on the 5.0 GT's, otherwise they dead-end. C232 is the port for the OBD-II diagnostics. Since I'm re-wiring the entire car, I put that connector in the center console where it's easy to reach.

It made a very neat installation (some people on this board seeing the photo of the harness said it looked OEM - I'll take that as a compliment) and the underhood wiring is completely stock. The local Ford dealer actually has done some work on my car since the Mod Motor was installed and they had no trouble with it. It was just like working on a Mustang.
'88 GT ready for wiring

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Figued this would be an appropriate place to ask this question. I've been wracking my brain with possibly switching out my rear with my 04 donors rear. figured it would be a upgrade since it has the 5 lugs and rear disk breaks. My question is what did you guys do to convert to 5 lug and rear disks? Is it as easy as swapping spendles or swapping the whole rear? I've looked and searched on here but couldn't find a write up on it.

1979-1993 Fox Body Mustang Wheel and Tire Guide!

Mustang Wheel & Tire guide and F.A.Q.
We get so many questions about what wheels fit which Mustang the best or which tires do you recommend for the best fit? We have decided to put it down on digital paper and go over what wheels we recommend for your Mustang.
What wheels and what tires fit my 1979-1993 Fox Body Mustang?
At Latemodel Restoration Supply we want to make it as easy as possible to select the perfect wheel and tire kit for your Mustang. Listed below are some of our most popular wheel and tire combo's that we have decided that are the best fit for your 1979-1993 Mustang!

1979-1990 Mustang:

The 1979-90 Mustang had a smaller front fender opening than the 1991-93 Mustang. Without clearance problems or tire rub, the best appearing and performing set up here is to run a 17x8 front wheel with a 245/45/17 tire and for the rear you can run a 17x9 wheel with a 275/40/17 tire with no clearance problems.
Now, If you want to run a 17x10.5 wheel with a 315/35/17 tire on the rear you can, however you will have to remove the rear quad shocks and modify the inner fender with a "Large hammer!". It can be done in your driveway in no time, but every Mustang is different! You may not have to do anything other than just remove the rear quad shocks.

Here is a basic guideline for backspacing for fox-body wheels:
7" width - 4.5" backspace
8" width - 5-5.5" backspace
9" width - 6" backspace
10-10.5" width - 6.5" backspace
Earlier (79-86) Fox body Mustangs, as well as 4-cylinder Mustangs won't typically accept greater than an 8"-wide front wheel due to strut-to-wheel clearance. An upgrade to 87-93 5.0 brakes, or SN95 brakes may be required if a wider front wheel is desired on a four cylinder or 4-eyed Mustang.
Here's a picture of a black LX hatch with 4-lug 17x8 and 17x10 sc wheels:

Here's the rear view of our own Scott Grimes' 93 coupe with 10.5" SVE wheels and 315/35/17 Sumitomo tires:

1991-1993 Mustang:

Pretty much the same as the 1979-90 Mustang, but remember, the 1991-93 has a larger front fender opening so you may be able to run a 17x9 wheel with a 275/40/17 front tire.
I say "may" here, again, because every car differs. Steering rack limiters can aid in allowing a larger wheel and tire combination on the front of your Fox body. They limit the travel of the rack, sometimes preventing tire or wheel rub on full-lock turns. Just don't use too many of them, or your turning radius will suffer.
The famous LRS "5-lug Conversion kit"

One of our most popular sellers is our 5-lug conversion kit which allows you to run certain 5-lug wheels on your 1979-93 Fox Body Mustang for added safety and looks. It also allows you to expand your wheel choices. We have made an easy to follow chart below to see what wheels are the best fit for our 5 lug conversion kit.
Wheels that fit our standard 5 lug conversion kit.
Here is a list of wheels that will work with the LRS 5-lug conversion kit without modifications:

95 Cobra R Wheel
94-95 17" "Tri-Bar" GT Wheel
94-98 16" Waffle Star Pony Wheel
94-97 Cobra Wheel
94-04 15" V6 Wheel
94-04 16" V6 Wheel

Weld Draglites
Weld Prostars
Weld Rodlites
Billet Specialties Street Lites

There are tons of other aftermarket wheels not listed here that will work with our 5-lug conversion. When picking wheels not listed here for your LRS 5-lug conversion, pay attention to backspace, width, hub center hole diameter, and hub depth.
Why can't I use any 5-lug Mustang wheel with Latemodel Restoration Supply's 5 Lug conversion kit?
The main reason that a lot of Mustang wheels will not fit is because for our standard 5-lug conversion kit we use a replacement front 5-lug rotor that still uses an outer bearing, What happens if you try to install aMustang Bullitt wheel? It will simply pop out the center cap and not allow it to stay snapped in. You can still use a Bullitt wheel on the front, but you will be missing a front center cap. Other factory 94-04 Mustang factory style wheels won't clear the larger center hub at all, causing a dangerous situation where the wheel will not seat on the rotor. In 1994 the Mustang went to a front hub assembly that did away with an outer bearing that caused problems in attaching late model wheels to your fox body Mustang!
If want to a 1994-2004 Mustang wheel that is not listed, like a Mustang Bullitt wheel, you can, but you have to get your self a set of 1994-2004 Mustang front spindles, brake calipers and hub assemblies and you will be ready to roll! Just like this clean 1989 Mustang Coupe with Bullitt wheels, Cobra R wheels or even factory Mustang Mach1 wheels! SN95 Cobra brakes also provide an added measure of safety, replacing either the 87-93 5.0's 11" front discs, or even the puny 4-eyed or 4-cylinder 9" rotors.
Here's a clean white coupe with 17x9 and 17x10.5" black bullitt wheels using SN95 brakes:
And a gray LX hatch with 17x9" Cobra R wheels and 13" SN95 Cobra brakes:
This blue 4-eye coupe gets the full Mach1 treatment with Bullitt 13" brakes and 17x8" factory Mach1 wheels:

What Mustang wheels can I run if I choose to stay with 4 Lug?

There are still several great choices out there if you choose to stay with a 4-lug rotor/axle/wheel. The most popular is the satin or silver "Cobra R" that is patterned after the 1995 Mustang Cobra R factory race car only with a 4 lug pattern. The SC is designed to look like a Fox Body Saleen wheel and has been a big hit also. For the purists out there it is hard to stray to far away from a good set of pony wheels. Factory equipment on the 1991-93 Mustangs this wheel still looks great after all of these years. No longer available from Ford, the aftermarket is catching on with 17" versions as well as a 16x7 like the factory ones.
Silver Cobra
Saleen Sc Style
Chrome 17" Pony
Black Saleen Sc Style
Chrome Cobra R
Silver 17" Pony

How do I clean my new wheels?
Making sure that your wheels stay clean is also important. Here are a few guidelines to follow. With Chrome wheels all you really need is soap and water. I have seen it before with a metal polish being used on chrome wheels and it can eat the chrome and leave your wheels looking horrible. If you want a little extra shine grab some windex. Same for your painted or machined wheels. All painted wheels have a clear coat so it you spray the wrong cleaner it will eat away your clear coat and leave your new Mustang wheels dull:( So just use soap and water and you will be in the clear!

Where the rubber hits the road. Which tires do we recommend and which are best for my Mustang?

Tires are always a topic of concern because what is expected of the tire for the vehicle it fits. In this case, tires for a Mustang, are meant to handle and perform well on the street and on the track. They are also expected to get you to and from school or work with little or no problems. Our main tire that we offer is a Sumitomo HTR based tire that offers a great performing, directional tread pattern that looks great and is an economical choice. (It also smokes well for burnouts!) We have had these tires on the street, on the road course and the drag strip with no issues. This tire is a great choice because it means that you don't have to pay the big bucks for a decent tire, even with shipping, and you can spend the leftover money you saved from your local "tire discounter" on more goodies for your car, girl, dog, etc.
Our other tire choices are from Nitto. Nitto's 555 has a stickier compound and is a better performing tire than the Sumitomo. Nittos are priced a bit higher than the Sumitomo as a result. The Nitto 555 is an awesome tire and everything you have heard about Nitto's outstanding reputation is true. This Nitto 555 tire is for the serious performer and LRS has them at prices at or better than anyone.
Drag Radials:
Drag Radials by Nitto and Mickey Thompson are for when there are no compromises and you absolutely have to launch hard every time on the strip. These DOT approved "race tires" have a smooth footprint for better takeoff and acceleration than most street radials, but yet can be driven on the street. Yielding the best performance, these tires will also wear quicker due to the soft compound rubber used in its construction.
Slicks are for the drag strip, period. These are completely smooth for the best acceleration on the track. Cannot be driven on the street.
If you are unsure of which wheel or tire combo fits your application feel free to email(info@latemodelrestoration.com) or call(254-296-6500) and one of our experts will get back with you ASAP with an answer to your questions.

Published Oct 15 2010, 08:05 AM by edavis
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Staff member
What about the IMRC?
You have two options:
1. Use the existing ones and just gut them out.
2. Purchase a set of IMRC Deletes (Below)


IMRC Deletes from Modular Mustang Racing

Svt Fox

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Staff member
I just used stock, composite imrc's and zip tied them open. I am not a fan of gutting them simply because, ford isn't making them anymore and I may want mine to function again one day.


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I did the same, if I could find the control box for a reasonable price I would make mine functional, they work great on my SVT contour feels like a four barrel carb comes in at about 3500 RPM.
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