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1982-1993 Mustang GT Modifications Guide

Table of Contents - 

CHASSIS, BRAKES, SUSPENSION, WHEELS AND TIRES

CHASSIS  /  BRAKES  /  SUSPENSION  /  WHEELS AND TIRES

ENGINE, EXHAUST, DRIVELINE

EXHAUST  /  GEARS  /  AIR TRACT  /  HEADS AND INTAKES  /  POWER ADDERS

CONCLUSION

RECOMMENDED VENDORS

1982-1993 Mustang GT Modifications Guide We have had lots of requests for ideas and opinions on performance modifications for 1982-1993 GT’s. Although the registry’s primary purpose is to document the original equipment on these cars for future restorations and to gather statistics relating to their originality, we cannot ignore the fact much of the 3rd generation GT’s popularity is due to the relatively cheap performance gains that can be had by modifying these cars. As a matter of fact, way over half of the GT’s we have registered have been enhanced by performance modifications ranging from mild to wild. The 1982-1993 Mustang GT Registry does not discriminate against stock OR modified - we like both equally and this is why we’ve decided to provide you with this guide to making modifications to your GT. Please understand that the following is just the Registry’s opinion and is NOT gospel. As the saying goes... “your mileage may vary.” All modifications are done at the owner’s risk and the Registry assumes no responsibility for what may or may not work on your car. Although most of the modifications mentioned in this article will work for all 1982-1993 Mustang GT’s, some modifications noted here only apply to 1987-1993 5.0L electronic fuel injected GT’s. Now, if you are considering buying a 3rd generation Mustang GT and you’re planning to make performance modifications, we suggest you seriously consider buying a 1987-1993 GT since the earlier models (1982-1986) don’t sport the upgraded engines, brakes, transmissions, rear ends, suspensions and exhaust systems of their later siblings. This way, you start with a better performing car from the very beginning. However, don’t be discouraged if you already have a 1982-1986 GT - many performance improvements can be made to these models, too! Don’t forget that it’s relatively easy and cheap to simply add the pieces from later GT’s that were upgraded over the years. For example, a 1982 GT’s performance can be improved by adding the true dual exhaust from ‘86 - up GT’s, bigger front brakes from ‘87 - up GT’s, the four barrel carb / intake set up from an ‘85 GT, the 8.8” rear end from ‘86 - up GT’s, etc. Frequently, these parts can be found for a very low price as take-off items from newer GT owners who are modifying their cars with aftermarket performance parts. For those of you with the ‘83 - ‘84 four cylinder turbo-charged GT’s, there are also factory performance part upgrades available from the ‘84 - ’86 SVO’s such as their intercooler system, etc. For a detailed listing of the Mustang GT improvements made from year to year, please see our "Year By Year" section. With these items in mind, let’s get started!

Additional Recommended Reading If you want to learn a whole bunch more about modifying your GT, we recommend that you consider purchasing the following books through our bookstore: Mustang Performance Handbook : Engine & Drivetrain Modifications Mustang Performance Handbook 2 : Chassis & Suspension Modifications How to Tune & Modify Your Ford 5.0-Liter Mustang 1979-1995 Check out our on-line (in association with Amazon.com) for even more great books on modifying your Mustang.

CHASSIS, BRAKES, SUSPENSION, WHEELS AND TIRES

CHASSIS

Well, to start with, we feel the first place to modify a 3rd generation Mustang GT is the chassis. The Fox body cars are notorious for their soft, flexible chassis and that’s where a person needs to start first and foremost. Remember, it does no good to have lots of power if the chassis, brakes and suspension can’t handle it. Ford Motorsport makes a nice chassis brace as does HP Motorsport. We recommend going with the full set of braces including the lower chassis/K-member/G-load brace, subframe connectors and strut tower brace. (NOTE: Ford Motorsport does not offer the lower chassis/K-member/G-load brace).

BRAKES

After getting the chassis well-braced, we would recommend addressing the brakes next. Again, Fox Mustangs are known for notoriously bad brakes. A nice upgrade for a little bit of money is to go to the SVO Mustang front brake calipers. These are a 73mm piston as opposed to a 60mm piston in the stock calipers (‘87 - ‘93). In addition to these calipers, you WILL need the SVO master cylinder in order to have a firm pedal. Another brake upgrade we highly recommend are HP Motorsport’s Stainless Steel brake lines. These work GREAT in making the brake pedal firm by eliminating those spongy, flexible rubber lines. If you want to go that extra step for the front brakes then you can step up to the Cobra brake kit (Ford Motorsport part number M-2300-K) or go with Baer Claw’s brake set up (NOTE: you will need 17” wheels with the Cobra brakes - you can fit the Baer Claws on 16” wheels). Last but not least, are new performance brake pads for the front brakes. We have had great luck with Performance Friction Brake pads. These work great for the street or the track.

Next up are the back brakes. Here you can go with 3 primary choices. The Cobra and Baer Claw kits come with the back brakes included so you won’t have to worry about this if you buy one of these kits. On the other hand, if you go with the SVO front calipers, a nice match is the Ford Motorsport rear disk brake kit (Motorsport part number M-2300-C).

For horsepower over 325, we would recommend the Cobra or Baer Claw brake kits. However, for even a stock car, the stainless steel brake lines and pads are a great upgrade and highly recommended.

Lastly, don’t forget to change your brake fluid on a regular basis. We change ours every Spring and more frequently if we are racing. We use Ford’s Heavy Duty Brake Fluid and have had great results with it on the track. This type of high performance brake fluid has a higher boiling point than regular brake fluid and really improves the performance of your braking system under hard use.

SUSPENSION

Here we would recommend a set of springs and struts/shocks to lower the car and firm up its handling. For springs, Eibach or Ford Motorsport get the nod (the Motorsport springs that we have seen need the back springs cut to get the car to sit properly, however). There are a variety of performance struts/shocks available and we feel that the adjustable types are well worth the money. With adjustable shocks, you can set them on soft for your daily commute to work and change them to a firmer setting to do your weekend autocrossing or open tracking. We have had Koni adjustable struts and shocks on our ‘91 GT for a number of years. In our opinion, you can’t beat the Koni’s for their adjustable settings and their lifetime guarantee. As far as other suspension mods go, another nice suspension upgrade would be to add beefier rear lower control arms. From here you can step up to more advanced pieces such as a panhard rod, upper control arms and other suspension pieces depending on what your particular application is.

WHEELS AND TIRES

There are a lot of great tires out there. Our advice is to talk to a bunch of the different Mustang owners and get their views on what tires they like and dislike. For the record, we have loved our BFG’s and we are on our second set. The wheel market is HUGE and usually your decision on which type and brand of wheel to buy is going to depend a lot on personal preference and the type of application you’re using.

ENGINE, EXHAUST, DRIVELINE

Now, after you have addressed the chassis, suspension and brakes, we feel you can move on to power upgrades. Remember, an engine is just a big air pump so the more air you can get in and out, the more power you make. The biggest cork in the airflow of the 5.0L motor are the factory heads. This is the best place to start making engine modifications however it is also the most expensive place to start. Luckily, there are many cheaper and easier modifications you can do to help your Mustang perform better and go faster.

EXHAUST

To make this easier on the budget, let’s start with an easy power upgrade. The cat-back exhaust systems are an easy modification and, besides adding power, they make the car sound great. We love the sound of our Flowmaster Force II’s. On the other hand, a friend of ours put on Dynomax mufflers and he’s very satisfied. They are a little quieter than the Flowmasters in addition to being a little cheaper in price. Next up on the exhaust side are headers and, depending on the use of the car, off-road h-pipes or high-flow cats. For headers, you can go with full-length or unequal-length shorties or equal-length shorties. One draw back with equal-length shorties is that you will probably have to raise the motor to get these on the car. Finally, it is highly recommended to get the headers with ceramic coating to lower under hood temps and keep them lasting and looking good.

GEARS

One of the best modifications you can make to your car for "seat of the pants" performance is a rear axle gear swap. Of course, everybody has an opinion on which gear ratio is the best to run. Popular gear ratios are 3.55’s, 3.73’s or even 4.10’s The best we can tell you is talk to a lot of people and get their opinions. If possible, find somebody that will let you drive their car with the gears you are considering in it.

AIR TRACT

Once the exhaust side is done, you can then start on the air tract from the filter up to the upper intake (on EFI cars). Here, one of the first modifications people make is to remove the air intake silencer (hidden in the fender), but HANG ON TO THIS!! Don’t throw this piece away because someday if you ever want to show in a concours class you will need this. Next up is the air filter and the most popular choice for performance is a K+N Filter Charger. Of course if you have a later ‘80’s and ‘90’s GT’s equipped with a mass air meter you have another choice to make for a performance upgrade. There is a wide variety of different mass air meters that are out there. Here again depending on your applications and how fat your wallet is, different meters work better. We have great luck with our Vortech/C+L 73mm unit. Other good meters include the Ford Motorsport unit and the Pro M unit.

From here, on EFI cars, we go to the throttle body. We are using the Motorsport’s 65mm TB and spacer (part number M-9926-A302 TB and M-9474-A50 for the spacer) and we have had no complaints with them. This unit comes ready to bolt on with a new idle air by-pass valve and thottle position sensor on it. Another very popular unit is the Edelbrock. This they make a variety of sizes depending upon your application. The most popular size in this brand that we have seen is the 70 mm. On this brand (as well as on other aftermarket brands) you will need to add the idle air by-pass valve.

Of course, on carbureted cars, there are lots of great aftermarket performance carburetors out there. We highly recommend talking to others who have made this switch if you’re considering an aftermarket carburetor to see what works and what doesn’t.

HEADS AND INTAKES

Okay, now, we start to get into the $$$$$$$$. We feel that to get the most out of the upper intake you need to change the heads and vice versa. Trust us, after pulling off the upper intake once, you won’t want to take off and put back the upper intake twice - once to do the intake and once to do the heads. Do the intakes and heads at the same time! Let’s look at upper intakes first. Number one on our list is the Ford Motorsport GT-40 (part number M-6001-A50). This unit looks great and air flow is good up to 425 horsepower. Another offering from Ford Motorsport is the Cobra intake (part number M-9424-D51) This unit will support up to 400 horsepower. Both come with upper and lower intakes. Other available intakes include the Saleen/Vortech, Edelbrock and the “bread box” style, however these bread box styles work better on more modified engines.

Now, on to the most costly engine upgrade - the heads... remember, this may seem like a lot of money but this is the major problem of the 5.0. Here once again, we chose a Motorsport part - their GT-40 aluminum heads (part number M-6049-Y303) and these are good for a 40 horsepower jump in addition to lightening the front end by 25 pounds per head. True to our bad luck, after we bought our GT-40 aluminum heads, Motorsport released an even better GT-40 head, the GT-40X aluminum head (part number M-6049-X303 for the 64cc chamber and M-6049-X305 for the 58cc chamber). These heads add 65 horsepower over the stock heads. Once again, these lighten the front by 50 pounds. Last but not least from Motorsport, are the heads that started it all, the cast iron GT-40’s (part number M-6049-L303). Other nice-looking aluminum heads include the new TFS Twisted Wedge heads. These heads have been dynoed to add 70 horsepower over stock heads and are priced very reasonably. Other popular heads include the aluminum Edelbrock heads, Dart, Trick Flow Specialties (TFS), etc. We recommend going with aluminum heads for the weight savings. Although porting stock heads is a popular performance upgrade, we feel that by the time the stock heads are ported and better valves are put in you’re better off going with the above mentioned units.

POWER ADDERS

Last is the subject of power adders (i.e. superchargers, turbochargers, stroker kits and nitrous oxide). Now, we don’t have first hand experience with any of these items but we have talked to a lot of owners with them on their cars and, if a major cash flow would come in our door, we know what we would go with. There is a huge market for superchargers with the major players being Vortech, Paxton, Ford Motorsport/Powerdyne, BBK, and ATI. All of the different brands have their positives and negatives. Our advice again would be to research what you want to use the blower for, i.e. track events or street, and talk to people that own them to make your decision. Others in the power adder category are nitrous oxide systems, turbochargers and stroker kits. Typically, nitrous is mostly for drag racing and although it has its pluses and minuses, in the bang for the buck category it’s hard to beat. Turbos are generally more expensive than superchargers and most aren’t EPA legal. Stroker motors are another area where you are going to have to do lots of research. They make a lot of different combinations which range from 306 cubic inches up to 357 cubic inches out of a 302 block. It’s a neat way to gain horsepower with out advertising it!!

Finally, one other thing to touch on is the use of synthetic oil and fluids. We highly recommend them as they will give you increased power and longer engine life.

CONCLUSION

Well, that’s the major stuff, but don’t forget the other odds and ends that go with these modifications such as fuel injectors, fuel pumps, drive shafts, transmission, clutch, shifter, rear end, ignition system. All of these need to be in good condition and should be able to work with your other modifications. Most importantly, if you are adding power, be sure your drive train will absorb it!!

Note: There are many new products and vendors coming on the market everyday – there may be newer vendors and products that aren’t mentioned here in our write-up.  

RECOMMENDED VENDORS

We have used the following vendors to buy the above products from and highly recommend starting your search with them:

DIVERSIFIED PRODUCTS MARKETING INC. is a great place to buy your Ford Motorsport products at a great low price. As a top ten Ford Motorsport dealer they are more than willing to check the price of anything in the Motorsport catalog for you. We have gotten a lot of our Motorsport parts from them and their service is # 1 - you call for the part and it goes right out. . Their number is 734-459-0130 - they will be more than willing to help you out in your search for the right part.

HP MOTORSPORT is located in Omaha, Nebraska and we have had great luck with their parts, service and advice. They are the ones that changed our GT from an AOD into a 5 speed and, if you didn’t know it originally had the automatic in it, you would swear it came from the factory as a 5 speed car. They carry Ford Motorsport products, their own products including braces and lower rear control arms and lots of other pieces for the Mustangs including wheel and tire packages. They also carry superchargers and many aftermarket products. Give them a call and Paul will be able to help you out. Their phone number is 402-731-7301.

FORD MOTORSPORT TECHNICAL ASSISTANCE "HOT LINE" - (810) 468-1356: This is the place to call if you have any questions regarding any Ford parts or adding a Motorsport part to your car. They can help you with any number of technical questions such as if a part you are considering will work for your particular application.

EBAY (on-line auctions):  For those of you on a budget, ebay can be a great place to find practically any kind of second-hand performance part for typically a very good price.

OTHER VENDORS can be found on our links pages.