I wonder what kind of power....

The effects of any changes are dependant on the rest of your combination. The first modifcation you do doesn't add much power, while the last thing you do can add a lot. For a relatively stock Mustang, the first three won't do much. The exhaust and intake will likely get you 5-10HP each, depending on the combination (could be more if you had aftermarket heads). A 70mm throttle body is too big unless you have done heads and such, or have stroked the engine. On a relatively stock car, a 65mm throttle body will gain you 2-5HP, more if it's heavily modified. A book titled 5.0L Ford Dyno Tests by Richard Holdener lists dyno results for various changes on a 5.0 engine, and shows what works and what doesn't. Mass air flow sensor, underdrive pullies, and 1.7 roller rockers could be added to your list, though the biggest difference is obtained with aftermarket heads (or a supercharger).

Leave the smog stuff alone. Besides, if you take that off, what's the point in leaving the cats on? MSD stuff is a complete waste of time, especially with an otherwise stock car. The stock ignition is good to 400 hp +/-.

Removing the pollution control equipment from a 5.0 Mustang is a bad idea. All you have accomplished is to make the computer mad and spit codes. The pollution control equipment all shuts off at wide open throttle, so the HP losses from it on the car are 2-5 HP. The catalytic converters may soak a few more HP than that. None of the pollution control equipment reduces the HP enough to cost you a race in anything but professional drag strip competition. You would not notice any difference in around town performance.

Know what does what before removing it. Remove or disable the wrong thing and the computer sets the check engine light and runs in "limp mode". Limp mode means reduced power and fuel economy.

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 $30-$50 from Borders.com see http://www.amazon.com/ . Select boo...l Supply Equipment from MSC Industrial Supply or McMaster-Carr if you can't find the drill bit or tap locally.

The next best spot for the ACT is the stock air box if you don't do the drill and tap thing. You get to cut and splice the 2 ACT wires in order to make them long enough to reach the air box. Solder the wire extensions on the existing wires & use heat shrink tubing to cover the splices. Offset the place where you cut the wires so that you don't have a big bulge when you put heat shrink over the 2 wires to cover & protect them. The air box gets a hole (5/8" or so) for the ACT drilled about 1 1/4" down & 1/1/4" in on the front top side near the upper radiator hose. A brass fitting nut from Home Depot or Ace Hardware secures the ACT into the air box.

If you are very clever, you will find that the ACT connector comes apart so that you can remove the pins. A very small screwdriver releases the lock in the front of the center insert, while another small screwdriver inserted in the back pushes it out. Once the center insert is out of the connector shell, the pins come out easily. New pins are available from AutoZone in a $5 electrical pin kit for Fords. Crimping the pins on the extender wires saves you from having to splice them twice: once to put the connector on and once to extend the wires.

6 ft black 18 gauge wire
6 ft green 18 gauge wire
6 ft 1/4" heat shrink tubing
1 ft 3/16" heat shrink tubing

Measure the 2 extender wires & cut them to length, crimp one set of pins on them. Then mate up the extender pins with the wiring harness & slide the 3/16" heat shrink tubing over them & shrink the tubing. Then slide the 1/4" heat shrink tubing over the pair of wires and shrink the tubing. When you are done you'll have about 1" of wire left without heat shrink tubing on it to strip & crimp the new pins on. Stick the new pins in the old connector shell, assemble it and you are done. It looks as good as factory. Some wire loom can be used to enhance the "Factory Look".





Use the TPS and IAB from your old throttle body. All the EGR passages were there and fit OK. Use you old fuel rails and regulator. You will probably need a new EGR spacer adapter and gaskets. Without the EGR spacer, there is no place to mount the throttle linkage support bracket.

I used the stock water lines on the Explorer manifold and they connected up to the EGR without any problems. I made a “U” out of ½” copper pipe and sweat soldered it together. Then I used it and some hose with clamps to bypass the leaky heater I have. You don't need heat very often here in Central Florida...

The vacuum lines you need are 1 small line for fuel pressure regulator, 1 small line for A/C,1 small line for EGR and another small line for the smog pump. One big line at the back goes to the vacuum tree for the power brake & A/C, one big line goes to the PVC valve. The other big line goes out the front for the carbon canister. In a pinch, one of the small lines can connect to the spare port on the vacuum tree. Cap or plug the remaining lines since they aren't needed.

The stock Explorer linkage didn't come anywhere near fitting, so I made an adapter plate for the throttle linkage so I could use the 65 MM throttle body.

This is what I did:
Make a drawing of the position of the old throttle body linkage arm and its angular position relative to the centerline of the throttle body. Remove the ball stud off the explorer TB to make way for the adapter plate. Drill and tap a 10-32 hole in the linkage parallel to the TB shaft. Make an angle bracket out of 1" angle iron 3/8", drill a 3/16” hole in the center of each one of the legs. Then bolt it on where the hole was drilled & tapped. Then make a circular adapter plate out of 1/4" thick aluminum to bolt the two linkage arms together. Then bolt the aluminum plate to the existing linkage, and the angle bracket. Next mount the arm with the ball stud off the old throttle body on the adapter plate using the drawing to get the angle correct. You will need an aircraft type countersink for one of the bolts that secures the plate to the explorer linkage arm. It ends up being under the arm with the ball stud for the linkage. It works great and looks neat.

The Explorer TB could have been real simple if I had a gas welding torch or taken the TB to a welding shop. Just grind the mushroomed part of the TB shafts so that you can pry the linkage arms off. Then swap the stock arm onto the Explorer TB and braze it onto the shaft. It Takes about 3 minutes or less worth of work with the torch, so it shouldn't cost much.

I didn't have access to a welder, so I fabb'ed the plate in my shop. I took about 1.5 hours to do it, it was a measure, cut, and fit type of operation.

Also see http://www.veryuseful.com/mustang/tech/engine/ConvertingExplorer65mmTB.pdf for modifications to adapt the 65 MM Explorer TB to a Mustang

Vacuum line connections:
One large vacuum line from the upper front goes to the carbon canister

One large vacuum line from the rear goes to the vacuum tree.

One small line in the front feeds the Smog pump solenoid control valves on the rear of the passenger side wheel well..

One small line in the rear goes to the fuel pressure regulator.

One small line in the rear goes to the EGR suction regulator.

One large line in the rear goes to the PVC valve.

Diagram courtesy of Tmoss & Stang&2birds - Typical Vacuum Routing for a Fox stang 5.0:

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information

Here's some tips...

Tools: a good torque wrench is a must have item. A razor blade scraper that holds a single edge razor blade from Home Depot or Ace hardware is another handy thing. Get a Chilton or Haynes shop manual - you'll need it for the bolt torques and patterns. The intake manifold has an especially odd pattern. You'll need access to a timing light to set the timing after you re-stab the distributor. Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling. Put some motor oil on them when you put the line back together.

The A/C Compressor comes off with lines still connected. Mark all the electrical, smog and vacuum lines with tags to help you remember where to re-connect them. If you have a digital camera, take several pictures.

Whatever you do, don't skimp on cleaning the gasket surfaces. New gaskets need to seat against bare metal and not the residue left from the old gaskets in order to seal leak free. This is the most time consuming and tiresome part of the job. Cut a piece of cardboard to fit the lifter valley and help catch all the crud scraped off the gasket surfaces. I suggest that you make good use of a shop vac while you are scraping and cleaning to avoid getting the old gasket material lost inside the engine. Look for little things that need to be replaced like the short hose from the thermostat hosing to the water pump, damaged vacuum lines and hose clamps that are rusted or broken. Cut a piece of cardboard to fit the lifter valley and help catch all the crud scraped off the gasket surfaces.

Plan on cutting the thermostat to water pump hose, or removing the thermostat housing. Also plan on removing the distributor to get clearance to remove the intake manifold. Remove #1 spark plug, stick your finger in the spark plug hole and crank. When your finger gets air moving past it, stop cranking. Turn the engine until the timing marks line up with the pointer. Now you can pull the distributor out. Be sure to put a rag or cap in the block where you removed the distributor. It will save you trouble if something falls into the empty distributor hole.


My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.

When the surfaces are clean, use weather strip adhesive on the head to manifold surface. Also use the weather strip adhesive on the side of the gasket that mates to the head. When you are done, the head surface and the gasket surface that mate together will have weather strip adhesive on them. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.

Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.

Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. TADA! no leaks, and no gaskets that shifted out of place.

Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $2.74 per kit. The following are listed at the Borg-Warner site ( BWD - Home ) as being resellers of Borg-Warner parts:

Parts Plus - Premium Auto Parts & Accessories or Auto Value / Bumper to Bumper Quality Parts & Service - Home of the Aftermarket Auto Parts Alliance Group or Auto Parts & Auto Service - Automotive Tires & Car Care | Pep Boys Auto - Parts & Service or Federated Auto Parts - Automotive Aftermarket

Most of the links above have store locators for find a store in your area.

Use motor oil on the O rings when you re-assemble them & everything will slide into place. The gasoline will wash away any excess oil that gets in the wrong places and it will burn up in the combustion chamber.

Plan on doing an oil change within 2 hours of run time on the engine. This will get the debris and coolant out of the oil pan.

Consumable items:
Upper manifold gasket
Fel Pro 1250 or equal lower manifold gasket set.
Short formed hose between thermostat hosing and intake manifold
6 ft 7/64" or 1/8" vacuum hose
2 ft 1/2" heater hose
1 1/2 ft 5/8" heater hose
Blue Silicone sealer
ARP antiseize or equal for the bolts
4 each 3/4" hose clamps (spare item in case the old ones are bad)
4 each 1/2" hose clamps (spare item)




On a budget? do the junkyard upgrade...

Gears - 87-88 T-Bird Turbo Coupe rear axle - disc brakes and 3.55 or 3.73 gears in one package for $125-$300. Add another $100-$200 or so to complete the brake upgrade.

94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes. *1 *2

95-97 Ford Explorer intake manifold & throttle body $150-$300. The intake manifold flows 220 CFM +, much better than stock. Throttle body is 65 MM, bigger than the 60 MM on stock stangs. I got a 96 with EGR passages that match the stock setup, so my smog gear works just like factory. You’ll need a 65 MM EGR spacer & new gaskets for $65-$90 so you have a place to mount the EGR & throttle linkage.

3G alternator from 94-95 Mustangs or other Ford. $20-$120. A must have to make the electrical system work like it should or if you have an electric fan. You’ll need a 4 gauge power wire and a 125-135 amp fuse to go with it about $15- $30.

Lincoln MK VIII electric fan -$40-$160. Free up some HP by not having to drive the stock fan. The 3G alternator upgrade is a must have prerequisite before you do the MK VIII fan. You won’t have enough electrical power if you don’t do the 3G upgrade.

Aluminum driveshaft: (courtesy of shawn13) It needs to be from a 92-93-94 Aerostar AWD. It measures 45 ½” center of the front U-joint to center of the rear U-joint. You will need the U-joint, part #PUJ353 from NAPA. The Canadian NAPA pat number is 1-0134BF. It should bolt right up after the U-joint swap.

Note: This driveshaft is not an exact duplicate of the Ford Racing part. It is 3” in diameter while the Ford Racing part is 3.5” in diameter. There is no guarantee that the balance will be any better than the stock part.

Use a piece of string and wrap it around the driveshaft. Make a mark on the string where the ends overlap. Measure the length of the string:
On the 3" AeroStar driveshaft the string will be 9.42" or about 9 7/16" long.
On the Ford Racing 3.5" driveshaft the string will be 10.99" or about 11" long

*1.) Metal flange adapter Ford MAF Adapters - Air Filters - Kurtz Kustomz Motorsports, Inc. KKM Buy the TR70 for $40. Or spend some time on eBay looking for one that may fit.

*2.) MAF & sensor interchange
The 94-95 Mustang 5.0 MAF & sensor is also found on:
1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.

Only thing on your list I would do is an Edelbrock Performer intake, 70MM Throttle body and I'd change the MAF to a 77MM while I was at it. My car gained right around 40HP at the wheels with all this and received my first 13 second 1/4 pass, it was the best mods to date at the time. The rest of your items will require money but won't net you HP gains. I'm guessing you still have smog testing in your area? I would run an off road pipe and then put the stocker on for smog testing. Don't know if that' feasable in your area but that's what I did when we had testing. After all this save up for Long Tube Headers, shorty off road pipe (or with cats if you must) and cat back.

Don't forget to have the basics done already-bumped timing, removed air silencer, underdrive pulleys (cheap mod), MGW Shifter or equivalent, Gears at least 3:73's, suspension-springs, probably most of the bushings under the car are wiped after 20 years, look into upper / lower control arms.

VibrantRedGT said:

Only thing on your list I would do is an Edelbrock Performer intake, 70MM Throttle body and I'd change the MAF to a 77MM while I was at it. My car gained right around 40HP at the wheels with all this and received my first 13 second 1/4 pass, it was the best mods to date at the time. The rest of your items will require money but won't net you HP gains. I'm guessing you still have smog testing in your area? I would run an off road pipe and then put the stocker on for smog testing. Don't know if that' feasable in your area but that's what I did when we had testing. After all this save up for Long Tube Headers, shorty off road pipe (or with cats if you must) and cat back.

Don't forget to have the basics done already-bumped timing, removed air silencer, underdrive pulleys (cheap mod), MGW Shifter or equivalent, Gears at least 3:73's, suspension-springs, probably most of the bushings under the car are wiped after 20 years, look into upper / lower control arms.

Click to expand...

40rwhp from a meter, intake and tb? That's a completely unrealistic number.
Probably off by somewhere around 20-25rwhp.

It's possible to get to 225rwhp or so with bolt ons, like pulleys, exhaust, timing. Adding 40rwhp to that would put you at 265rwhp. A number that some don't get by adding a complete h/c/i setup.

2000xp8 said:

40rwhp from a meter, intake and tb? That's a completely unrealistic number.
Probably off by somewhere around 20-25rwhp.

It's possible to get to 225rwhp or so with bolt ons, like pulleys, exhaust, timing. Adding 40rwhp to that would put you at 265rwhp. A number that some don't get by adding a complete h/c/i setup.

Click to expand...

My 94GT 215BHP in stock form dynoed under 200HP. I have the dyno sheet, it made 237HP / 241TQ at the wheels with Performer, 70MM TB and Pro-M 77 MAF. Mods at the time Headers, High Flow H-Pipe, Flowmaster Cat back, timing, maybe pulley's but not sure it was 1998. Went from 14.4 @ 93MPH to 13.91 at 97MPH or so. It's been documented on this site since 1999.