Necessary Mods To Achieve 400hp?

StreetSlayer99

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Sep 16, 2016
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Hey folks, I'm looking at buying either a 89 or 90 stock 5.0 GT. And im a 17 year old who works part time, and i was wondering which routes i should go that wont break the bank with the 5.0 to reach at least 400 horsepower. Just top end upgrades with a tuner? Scat kit? Im new to this car, but was drawn to it due to the body styling and how quick of a car it can be street/strip. Any opinions or ideas will be appreciated!!
 
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My advice, and it's worth EVERY penny you paid for it, is don't worry about some "magic" number just yet.

I see, and have seen for years, across every Mustang forum, a "how do I get to this much HP?" post on a daily basis.

1. There's no single answer. The easiest way is http://www.hotrod.com/articles/ford-302-v8-engine-buildup/ from an old Car Craft magazine article.
2. You need to do a lot more than build up the engine. If you JUST build the engine, other stuff WILL break.
3. Start here: http://www.stangnet.com/mustang-forums/threads/the-10-min-tune-up.756743/ and go drag race it (AT THE TRACK) until you're good at it, or you break something. THEN worry about upgrades. There have been guys that put fox-body cars into the 12s with nothing but bolt-ons to the suspension, that "tune-up" and a set of gears and tires.

400hp is nice, but it's not absolutely necessary for a fast/quick car. My Mustang puts down 267 at the rear wheels (350ish at the crankshaft), and last time out (granted, it was a couple of years ago, haven't found the time) it was in the 12.90s spinning the tires horribly off the line (car doesn't weigh much and has a lot of other work done to it).
 
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My advice, and it's worth EVERY penny you paid for it, is don't worry about some "magic" number just yet.

I see, and have seen for years, across every Mustang forum, a "how do I get to this much HP?" post on a daily basis.

1. There's no single answer. The easiest way is http://www.hotrod.com/articles/ford-302-v8-engine-buildup/ from an old Car Craft magazine article.
2. You need to do a lot more than build up the engine. If you JUST build the engine, other stuff WILL break.
3. Start here: http://www.stangnet.com/mustang-forums/threads/the-10-min-tune-up.756743/ and go drag race it (AT THE TRACK) until you're good at it, or you break something. THEN worry about upgrades. There have been guys that put fox-body cars into the 12s with nothing but bolt-ons to the suspension, that "tune-up" and a set of gears and tires.

400hp is nice, but it's not absolutely necessary for a fast/quick car. My Mustang puts down 267 at the rear wheels (350ish at the crankshaft), and last time out (granted, it was a couple of years ago, haven't found the time) it was in the 12.90s spinning the tires horribly off the line (car doesn't weigh much and has a lot of other work done to it).
 
Hey folks, I'm looking at buying either a 89 or 90 stock 5.0 GT. And im a 17 year old who works part time, and i was wondering which routes i should go that wont break the bank with the 5.0 to reach at least 400 horsepower. Just top end upgrades with a tuner? Scat kit? Im new to this car, but was drawn to it due to the body styling and how quick of a car it can be street/strip. Any opinions or ideas will be appreciated!!

Let's see

  • 17 year old
  • 27 year old car
  • works part time
  • wants 400hp

What could go wrong?
 
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Let's see

  • 17 year old
  • 27 year old car
  • works part time
  • wants 400hp

What could go wrong?

What could go wrong? All the same things I did wrong 23 years ago, except the car was only 3-4 years old and it only had 225hp.
Donuts, clutch drops, close calls of every kind.

But the thing that stands out most to me? One time I was driving the car hard stop light to stop light, then on the third stop I almost broke the seat pressing the peddle so hard so I didn't run a light. Having the brakes over heat is a life changing experience.


My advice, get the car, make sure it is mechanically sound.
Get some 5 lug wheels, do a 5 lug conversion with 94/95 spindles and rear discs. Rebuild rear at same time with gears.
Then upgrade the suspension.

After that start worrying about hp.
 
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Just to throw in the voice of non-reasoning. Vortech, the rest will get sorted out afterwards.
Recipe for disaster.
You need more knowledge about the car to run a supercharger.
The last thing he needs is to blow a head gasket and drive the car around for a month.
While a supercharger is no where near the headache of a turbo, they aren't without issues.
Older more experienced guys will likely recognize it, when someone just starting out probably wouldn't think anything of it and keep driving (been there).

He should avoid anything that could major damage, working part time probably means he doesn't have a large pile of cash to fix any catastrophic damage.

You have to learn and grow with the car.
This way you don't break it or wreck it.

This circumstance may be one of the very few times i'd recommend the gt40p heads and explorer intake.
 
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Recipe for disaster.
You need more knowledge about the car to run a supercharger.
The last thing he needs is to blow a head gasket and drive the car around for a month.
While a supercharger is no where near the headache of a turbo, they aren't without issues.
Older more experienced guys will likely recognize it, when someone just starting out probably wouldn't think anything of it and keep driving (been there).

He should avoid anything that could major damage, working part time probably means he doesn't have a large pile of cash to fix any catastrophic damage.

You have to learn and grow with the car.
This way you don't break it or wreck it.

This circumstance may be one of the very few times i'd recommend the gt40p heads and explorer intake.
Thanks, I was being a smartass is all.
 
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5.0 Fox body Mustangs have their own set of problems for newbies; the engine is far more powerful than the stock brakes or T5 transmission can handle when vigorously driven by a novice. The suspension will not maintain traction control and it will swap ends when driven too energetically on wet or slippery pavement. Breathe on the accelerator too hard on a wet street and you'll find out what it feels like suddenly find yourself as passenger along for a frightening ride instead of an in control pilot.

If you don't have lots of solid mechanical and electrical skill, the car will be a nightmare. On the other hand if you have been fixing EFI cars since you were 12 and can troubleshoot and fix sensor and electrical problems easier than asking a pretty girl out for a date, it will not be much of a problem.


Welcome to Stangnet... :spot:

Not all of us know how to fix everything, but some of us know how to fix some things
with excellence!

Places to check out here on Stangnet:
http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/ How to do it tips for some of the most common problems and upgrades for 5.0 Fox body Mustangs.
http://www.stangnet.com/mustang-forums/threads/the-official-progress-threads-thread.761371/ the collection of build/progress threads from Stangnet members. You get to find ideas and clues to what works well and what doesn’t.
http://www.stangnet.com/mustang-forums/resources/ Has tech tips for common problems on Mustangs.

If you are in California or some other state with strict emissions laws, part of the deal should be that the owner takes the car and has it emissions tested. If it passes, you buy the car and pay for the emissions test cost, if any. If it does not pass, walk away from the deal. For a mechanically inexperienced owner, emissions related problems can be difficult and expensive to fix. Avoid any car that was originally EFI and has been converted to carb like the plague. That's often a clue to the fact the previous owner had problems and the resulting hack job has MORE problems.

Keep in mind that states with strict emissions laws may make the go faster goals more difficult to reach. Some parts are OK to replace with aftermarket parts and others aren't. Check carefully before you get out your wallet and buy something you can't use in the area where you live.


If you want to do the fix up & power up thing, make sure that you have some other form of reliable daily driver. That way the stang can sit while your wallet and hands take a rest from the last project that didn't quite get finished on that 3 day weekend. Things always cost more and take longer the first time you do them. Having some other working vehicle makes life easier since it isn't the big crush to get it running for the Monday morning drive to work or class.

Plan on spending some money on tools it you don't already have them. The stang has both metric and American fasteners, so you really need two sets of wrenches. A timing light, digital voltmeter, vacuum gauge, compression tester, fuel pressure test gauge and fuel line coupler tools are some of the test & tuning tools you'll need. Visit the pawn shops and sometimes you can find a deal on tools & test equipment if you stick to well known name brands.

A sheltered work area is almost a must, someplace that you can leave the car in pieces without upsetting anyone. Some guys here have changed a transmission in the parking lot of their apartment in a rainstorm, but they will tell you it wasn't fun. Depending on where you live, a warm dry garage is a nice place to do the winter projects that stangs tend to become.

EFI (Electronic Fuel Injection) Computer - every stang after 85 has or had one: don't let it intimidate you. The computer based EFI systems are not hard to fix and most of the time they tell you what's wrong with the engine. Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst: ISBN 0-8376-0301-3.

It's about $35-$45 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search

Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.

For lots of great ideas and tech notes on upgrades and repairs, be sure to check
out http://forums.stangnet.com/showthread.php?t=643651 “Useful Technical Thread Index” sticky at the top of the 5.0 Tech forum.

Things that break often:
T5 5 speed manual transmission (syncros go bad, mostly 3rd gear)
TFI Module (Thin Film Ignition module - mounts on the distributor)
Electric door locks (see the link in my sig for a cheap & easy fix)
O2 sensors(oxygen sensors) They are good for about 60,000 miles and start to go downhill after that.
TPS Sensor (Throttle Position Sensor) causes flaky problems with idle & acceleration.
Fog lights -they overheat the wiring and cause the headlights to flicker. The fix is cheap and simple if you can do electrical stuff.
Harmonic Balancer – they separate between the hub and outer ring. A harmonic balancer puller is a must have to change it. You can rent or borrow a puller from most of the larger auto parts stores.

Things that are very durable: Engine - as long as it hasn't been abused, it will run good for 150,000-200,000 miles without an overhaul
Rear axle - other than an occasional case of worn clutches in the traction lock, they almost never have problems.
Computer - believe it or not, the computers seldom have problems of their own. Most of the problems are with the sensors and the wiring.
Suspension – the front and rear suspension has very few problems if the car hasn’t been wrecked or seen a lot of drag strip runs. The drag strip runs tend to distort and tear the mount points for the rear axle control arms. Revving the engine up to 4000 RPM and dumping the clutch with slicks or drag radials tends to break things.

Things that don’t break often but are hard to fix:
Water pump mount bolts – they corrode and shear off when you try to change the water pump.
Rear oil seal on the engine – lots of parts to remove to get to a $20 seal.
Power steering pump – the pumps are noisy and the pulley requires some special tools to remove and install. If you have the tools, they are easy to do. Again, the larger auto parts stores will rent or loan the tools for the pulley.
Power Steering rack - it is hard to get the toe in set so that you can drive the car to the shop to get it properly aligned.
Starter – the top bolt is hard to get a socket on if you don’t have the right combination of socket, universal joint and extensions.

Everything considered, 5.0 Mustangs are not hard to work on. They just require some patience and though before you get started.
 
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Lets all give the OP good credit for wanting a Foxbody instead of some import with a fart can muffler.

An 89 would be great! First year for MAF, last year as a non-airbag car.
 
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5.0 Fox body Mustangs have their own set of problems for newbies; the engine is far more powerful than the stock brakes or T5 transmission can handle when vigorously driven by a novice. The suspension will not maintain traction control and it will swap ends when driven too energetically on wet or slippery pavement. Breathe on the accelerator too hard on a wet street and you'll find out what it feels like suddenly find yourself as passenger along for a frightening ride instead of an in control pilot.

If you don't have lots of solid mechanical and electrical skill, the car will be a nightmare. On the other hand if you have been fixing EFI cars since you were 12 and can troubleshoot and fix sensor and electrical problems easier than asking a pretty girl out for a date, it will not be much of a problem.


Welcome to Stangnet... :spot:

Not all of us know how to fix everything, but some of us know how to fix some things
with excellence!

Places to check out here on Stangnet:
http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/ How to do it tips for some of the most common problems and upgrades for 5.0 Fox body Mustangs.
http://www.stangnet.com/mustang-forums/threads/the-official-progress-threads-thread.761371/ the collection of build/progress threads from Stangnet members. You get to find ideas and clues to what works well and what doesn’t.
http://www.stangnet.com/mustang-forums/resources/ Has tech tips for common problems on Mustangs.

If you are in California or some other state with strict emissions laws, part of the deal should be that the owner takes the car and has it emissions tested. If it passes, you buy the car and pay for the emissions test cost, if any. If it does not pass, walk away from the deal. For a mechanically inexperienced owner, emissions related problems can be difficult and expensive to fix. Avoid any car that was originally EFI and has been converted to carb like the plague. That's often a clue to the fact the previous owner had problems and the resulting hack job has MORE problems.

Keep in mind that states with strict emissions laws may make the go faster goals more difficult to reach. Some parts are OK to replace with aftermarket parts and others aren't. Check carefully before you get out your wallet and buy something you can't use in the area where you live.


If you want to do the fix up & power up thing, make sure that you have some other form of reliable daily driver. That way the stang can sit while your wallet and hands take a rest from the last project that didn't quite get finished on that 3 day weekend. Things always cost more and take longer the first time you do them. Having some other working vehicle makes life easier since it isn't the big crush to get it running for the Monday morning drive to work or class.

Plan on spending some money on tools it you don't already have them. The stang has both metric and American fasteners, so you really need two sets of wrenches. A timing light, digital voltmeter, vacuum gauge, compression tester, fuel pressure test gauge and fuel line coupler tools are some of the test & tuning tools you'll need. Visit the pawn shops and sometimes you can find a deal on tools & test equipment if you stick to well known name brands.

A sheltered work area is almost a must, someplace that you can leave the car in pieces without upsetting anyone. Some guys here have changed a transmission in the parking lot of their apartment in a rainstorm, but they will tell you it wasn't fun. Depending on where you live, a warm dry garage is a nice place to do the winter projects that stangs tend to become.

EFI (Electronic Fuel Injection) Computer - every stang after 85 has or had one: don't let it intimidate you. The computer based EFI systems are not hard to fix and most of the time they tell you what's wrong with the engine. Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst: ISBN 0-8376-0301-3.

It's about $35-$45 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search

Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.

For lots of great ideas and tech notes on upgrades and repairs, be sure to check
out http://forums.stangnet.com/showthread.php?t=643651 “Useful Technical Thread Index” sticky at the top of the 5.0 Tech forum.

Things that break often:
T5 5 speed manual transmission (syncros go bad, mostly 3rd gear)
TFI Module (Thin Film Ignition module - mounts on the distributor)
Electric door locks (see the link in my sig for a cheap & easy fix)
O2 sensors(oxygen sensors) They are good for about 60,000 miles and start to go downhill after that.
TPS Sensor (Throttle Position Sensor) causes flaky problems with idle & acceleration.
Fog lights -they overheat the wiring and cause the headlights to flicker. The fix is cheap and simple if you can do electrical stuff.
Harmonic Balancer – they separate between the hub and outer ring. A harmonic balancer puller is a must have to change it. You can rent or borrow a puller from most of the larger auto parts stores.

Things that are very durable: Engine - as long as it hasn't been abused, it will run good for 150,000-200,000 miles without an overhaul
Rear axle - other than an occasional case of worn clutches in the traction lock, they almost never have problems.
Computer - believe it or not, the computers seldom have problems of their own. Most of the problems are with the sensors and the wiring.
Suspension – the front and rear suspension has very few problems if the car hasn’t been wrecked or seen a lot of drag strip runs. The drag strip runs tend to distort and tear the mount points for the rear axle control arms. Revving the engine up to 4000 RPM and dumping the clutch with slicks or drag radials tends to break things.

Things that don’t break often but are hard to fix:
Water pump mount bolts – they corrode and shear off when you try to change the water pump.
Rear oil seal on the engine – lots of parts to remove to get to a $20 seal.
Power steering pump – the pumps are noisy and the pulley requires some special tools to remove and install. If you have the tools, they are easy to do. Again, the larger auto parts stores will rent or loan the tools for the pulley.
Power Steering rack - it is hard to get the toe in set so that you can drive the car to the shop to get it properly aligned.
Starter – the top bolt is hard to get a socket on if you don’t have the right combination of socket, universal joint and extensions.

Everything considered, 5.0 Mustangs are not hard to work on. They just require some patience and though before you get started.




Thank you Sir!
 
For the record, we aren't trying to scare you off.
Just making sure you understand and respect the car even at low power levels.
Compared to modern cars, the foxbody is extremely lightweight, no traction control, no antilock, no rear discs.

There is nothing to save you from yourself like newer cars.
They are drivers cars, handle it right it's rewarding, handle it wrong and you will have to get towed out of a ditch or worse. Sometimes i'm amazed I made it this far. There were days when I was 18 that I think I came out of 100% of the turns sideways everywhere I went.

Believe it or not, I had more fun with gears and minor bolt ons than I do now with much much more power.
 
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For the record, we aren't trying to scare you off.
Just making sure you understand and respect the car even at low power levels.
Compared to modern cars, the foxbody is extremely lightweight, no traction control, no antilock, no rear discs.

There is nothing to save you from yourself like newer cars.
They are drivers cars, handle it right it's rewarding, handle it wrong and you will have to get towed out of a ditch or worse. Sometimes i'm amazed I made it this far. There were days when I was 18 that I think I came out of 100% of the turns sideways everywhere I went.

Believe it or not, I had more fun with gears and minor bolt ons than I do now with much much more power.

Very true... back in the day I got into a lot of trouble with just gears, exhaust, bumped timing, and a short belt
 
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