TOP 5 Essential Modifications for 87-93 Fox Body Mustang 5.0

BEST BANG FOR THE BUCK IN THIS ORDER: Pull intake silencer, bump timing, high flow filter, under-drive pulleys, braided front brake lines, stiffer steering rack bushings, stiffer swaybar bushings, larger MAF body, caster-camber plates to max caster, and aluminum driveshaft. Anything else you do is a waste of money for tiny gains. Stock intake provides more torque than the Cobra intake so don't waste your money unless you're supercharging or changing to high flow heads. Stock headers are fine. Catbacks give you noise without any noticeable power gains and the drone becomes insane on the highway. Bigger throttle body does not provide noticeable power and will decrease low-end torque with stock heads. Also, don't install rear gears for $600 when you can buy a brand new Ford rearend with 3:55s, new bushings, new bearings and no gear noise for $800-$1000. With all that you're still slower than a new V6 Toyota Camry or Ecoboost Mustang around a track. The fox requires huge dollars to make it competitive by modern standards so focus on improving drivability (handling, braking, stable high speed cruising) and save your money for modifying a more modern and capable chassis like an S550.

Flowmaster all day. The true classic East Coast 5.0 sound. That's what I ran with an off-road H-pipe.

Subframe, headers.hpipe,gears 373s bye pass smog pump. Flowmaster 40

I was deep in the Mustang craze in the 80's and 90's. I ran a speed shop and most of my customers were 5.0 guys. The cars did not have issues with bending the body until you were running deep into the 11's with slicks, by the time you got into the 10's with no subframe connectors, I had seen rear quarter panels buckle at the top, but for a street car with street tires, they are completely useless and just add weight. Same for the strut tower brace, unless you are into corner carving it is just dead weight. Back then the basics were under drive pulley set (can create overheating and low charge on cars that are only driven inside cities light to light, not recommended for Auto trans), gears: 3.73 were most popular, long tube headers with full exhaust (shorty headers were not much better than factory ones), MAF upgrade if you had an 86-88, and finally you needed to deal with what made power which was airflow into the engine: throttle body, bigger MAF sensor, intake manifold, heads. cam etc... A 65/70mm throttle body and spacer was probably the most popular addition in the intake, but unless you port matched it to the intake, it was not doing much... Cars were never really fast until you basically changed the whole upper part of the engine from the heads up and the cam...

People buying these 30-40+ year old Fox Bodies? Get your brakes & suspension up to snuff before anything. Aftermarket kmember with new control arms. New power steering rack with bump steer end links. Power steering pump and hoses. Fresh sway bar end link and bushings. Strut tower brace with room for any aftermarket intake or carb setup you might use later. I would go stock springs all around. Weld in Subframe connectors with seat brackets. New rear control arms with bushings. Rear shock tower brace. New struts shocks and ball joints all around. Rebuild the rear with whatever ratio, but make sure to replace axle bearings and seals as well. New brake calipers, pads, new brake fluid and master cylinder. New wheel hub/front rotors. Motor/trans mounts. It's important to do all these before anything else. Why? Because it's safer, it'll respond better to horsepower gains, modifications will install easier. For example. If your motor mounts are bad, installing aftermarket headers on the driver side will almost be impossible without denting the header. With a fresh motor mount, you shouldn't have to modify the header at all. One of many examples. Lowering springs are a bad idea. They don't hold up well over time. Stock springs work just fine.

Ditch the intake baffle should be #1… doesn’t cost anything and you gain 5-7 horsepower. Sounds better when you open it up.

My '88 GT isn't a California model so it has the Speed Density rather than the MAF introduced for all Mustangs in 1989. SD can limit the performance of many performance add-ons. I installed a Kenne-Bell cold air system that really pushes the air, and it works quite well with SD. You mentioned honing the intake manifold for increased flow/HP - for several years, there was a company called Extrude Hone, an innovative system for expanding and polishing the ports and runners on the intakes. Together with a good port matching job, this process could add 60+ horsepower and was invisible to anyone looking under the hood.👍

The best upgrades on any Fox including the Cobra would be a Head, Cam and Intake upgrade...

You are exactly spot on. I did the same steps in the same order. Except when changing out the diff to 3:55 I junked the pathetic AOD and put in a World Class T-5. That in itself was a whole new driving experience. Thanks for your post.

Great advice, I've done everything you've mentioned. I bought my Mustang back in 1991 brand new. Strawberry red LX coupe 5 speed. It now has 55,000 original miles and I'm in the process of making it completely stock again. I will keep the subframe connectors and strut tower brace for now. Thanks for the info and I will be subscribing to you for future updates.

I put Flowmaster mufflers on my 1988 GT back in the 90's and it sounded awesome!

I sure wish I knew about the subframe connectors a few decades ago! I loved my’89 LX Sport hatchback, and drove it (probably too) hard all over Arkansas and Louisiana. By 20k miles, there were multiple cracks in the unibody on both sides, which rather concerned this then-green mechanical engineer! Interesting video, thanks.

Well you forgot some things that 75 amp alternator needs to go, cooling fans, and starter reduces weight less stress and is little better but the alternator helps keeps the 12 volt supply goes from like 12.8 to 14.1. Big difference I seen with these mods on my mild built 87 t top gt. But far as everything else is golden very informative

I had a 3.55 in my 1988 T-topped Mustang I bought from a Lincoln-Mercury Service Manager around 1990. Had most of the FMS catalog installed. When stock ones were selling for $10K+ at that time I got it for $7500 since he needed a little extra cash to buy a sail boat he wanted, had it on the side of road with a sign for cash only today.

It's surprising how many people overlook the cooling fan for power. A clutch fan can easily cost 15+ hp with the clutch disengaged, which is almost what you get from a gt40 intake, and installing an electric fan is a lot cheaper...

You should also mention the 2g to 3g alternator upgrade. The 2nd generation was prone to catch fire + only put out 65 amps

I hate to say it, but flowmasters snd the best on the foxbys! 👌😎

This stuff is right up my alley! Thank you.

That was a really well put together summary

3.27 gears are best for cruising on the Interstate at 85 mph. And also deliver decent gas mileage.