Swapping A 5.0L EFI & T-5 Into A Classic Mustang

Posted by on February 28, 2007 - more

Article Credits

Author: Fast64

Editor: Brent

The EFI 5.0 engine and T5 transmission swap is beginning to be a popular swap among classic Mustang restomodders. Restomodders are doing this swap for many reasons; they do it because its pretty easy to do but it has a high “cool factor” at car shows and on the street. I like it because when the hood is closed, people think you have a little 2bbl 289 with a 3 speed, its very sneaky. This swap is also nice for daily drivers because it cranks up the first time every time and runs good, unlike carbureted engines that my act up in cold or hot weather and gets excellent gas mileage do to the fuel injection and overdrive. The swap can be as easy or as hard as you make it.

If you get a complete donor car with everything you need it will be simple; if you decide to piece parts together you will more than likely run into headaches. It is a fairly easy swap because the engine bolts right in place and the transmission fits well. I went from a running and driving donor car to a running and driving classic in a month and a half, only working on the car around school and work. I did have all the parts I needed before I began the swap, but that should give you an idea on how long it will take. I give this swap a 4 out of 5 in difficulty (even though it is relatively easy compared to other swaps) just because there is alot of work involved, as with all engine and transmission swaps.

I would not recommend this swap if you are not comfortable working on fuel, cooling, or electrical systems or if you are not comfortable fabricating/welding. Of course, you can pay someone to do the things you can’t, but this swap would be very pricey if you did that. This swap can be done for around $1000 depending on how much you reuse from the donor vehicle, I spent a little over $2000 since I opted to use a new wiring harness. If you do feel comfortable working on every aspect of making your engine run, this will be simple, straight forward swap that you can do for fairly cheap.

Choosing an engine and transmission

A 1989-1993 5.0L 302ci and a t5 from a v8 car would be a good idea since this motor has a Mass Air Flow sensor as opposed to a speed density set up. A complete 1989-1993 donor fox Mustang with a 5.0 and a t5 would be even better since you will have most every part you will need on the vehicle. You can use an 1986-1988 5.0 but MAF is preferred over speed density by most people and most parts made for this swap are for MAF 5.0s anyway.

You can use a 5.0 from a 1994-1995 also, but again most parts made for this swap are for 1989-1993 5.0s. 1994-1995 sensors are different than 1989-1993 sensors and you will have to convert to 1989-1993 sensors to use most aftermarket EFI wiring harnesses. You will also want a t5, tremec 3550 or TKO if you choose to go aftermarket, or t5z from a v8 car from 1986-1993 because they are rated for more hp and torque than the 4 cylinder t5 transmissions. A 1994-1995 and also the 1999-2004 t5 will have to be retrofitted with an 86-93 tail shaft to work though. The 1999-2004 are perhaps the strongest T5s made, but they use digital read outs instead of speedometer gears. The tail shaft swap should fix this problem since you can use a speedometer gear setup with this.

You will be dropping the engine and transmission into your early model’s engine bay.

Classic Mustang Engine Bay

This is how the engine sits in the early model’s engine bay:

Classic Mustang Engine Bay With Motor

Classic Mustang Engine Bay With Motor Two

In this picture of the engine bay of the late model donor car, you can tell that the engine sat much further back than it will in the early model:

Fox Mustang with No Engine

Fox Mustang with Motor

What you want/need from the donor vehicle (89-93)

You want the complete engine and transmission as well as the yoke that goes into the transmission. Don’t forget the air intake from the mass airflow sensor back, the vehicle speed sensor on the transmission, or the shifter. You may also want the radiator from the donor vehicle as well as the radiator hoses (it will make life easier if you choose to keep the late model front accessories). You need the Barometric Pressure sensor found on the firewall and the Inertia switch found on the inside of the taillight panel in the trunk. You need the computer found inside the passenger kick panel; you will also need the entire EFI harness if you plan to modify it and use it. You need the gas pedal assembly and the throttle cable. You might also want to grab the starter solenoid, the battery, the coil, some of the fuel line in the engine bay, and anything else you think you might need.

Oil pan and pickup

The late model 5.0s use a rear-sump oil pan and pickup, while the early small blocks use a front-sump oil pan and pickup. The rear-sump pan won’t fit into your classic because the k-member in your classic gets in the way. You can reuse the old pan and pickup from your original motor or buy new ones; the pickup only costs about $10 and it’s not a bad idea to replace it. It makes life a lot easier if you swap these parts onto your motor before it goes into your car. Don’t forget to prime your oil system before you crank it up.

Here you can see the classic style front sump oil pickup:

Classic Mustang Front Sump Oil Pickup

Here you can see the late model rear sump oil pickup:

Fox Mustang Rear Sump Oil Pickup

Engine and Transmission Mounts

The 5.0 is the same size as every other Ford small block so it will bolt into your classic with no problem at all. You will use the motor mounts for a 289 or a 302 for your year car. You must buy a transmission cross member made for the swap; they are available through a variety of companies such as Windsor-Fox, Dark Horse Performance, and Mustangs Plus. Some cross members reuse the original t5 transmission mounts and some include a new mount.

Here are several views of the transmission crossmember and mount, including one picture of the transmission installed in the car:

Mustang Crossmember

Mustang Crossmember

Mustang Crossmember

Clutch and Pedals

The late model block doesn’t have a boss for the early Mustang z-bar clutch linkage, but its crap compared to your other clutch options, so you don’t want to use it anyway. Now you are left with two options: cable or hydraulic. Cable clutches are much more simple to install than hydraulic clutches and cheaper too. Cable clutches can be purchased from MustangSteve, Mustangs Plus, and Mustang Depot. I recommend Mustang Steve’s kit because it is inexpensive and easy to install. The only problem I ran into installing this kit was the fact that you have to raise to cowl floor to have room for the clutch quadrant, A butane torch and a ball peen hammer made easy work of this though. A hydraulic clutch will be more pricey, but will have smoother shifts than a cable clutch. JMC sells hydraulic clutch conversions for classic Mustangs with t5s, tremecs, and even t56s. If your Mustang was originally equipped with an automatic, you will need to find the brake and clutch pedal assembly from a manual equipped car. I suggest eBay Motors for finding the cheapest pedal assemblies. I got my refurbished assembly for under $200. You will also need a gas pedal that utilizes a throttle cable; your existing pedal won’t work because its utilizes a mechanical throttle linkage. A gas pedal from a 69-70 Mustang will work, as will the gas pedal from your fox body donor car. The fox body pedal requires a bracket for it to function fully, and you can purchase one from Windsor-Fox or fabricate your own. I chose to save the $70 and mount mine to the inside of the firewall using some 2″ bolts and some spacers.

You can see below that there isn’t much involved with the MustangSteve cable clutch conversion. All you need to do is weld the quadrant to the clutch pedal, drill a hole in the firewall, mount the firewall adjuster, and then run the clutch cable.

Mustang Steve Cable Clutch Kit

Driveshaft

You can reuse your original driveshaft, but you need the yoke from the back of the T5. You will need a driveshaft shop to put a new universal joint on that will connect the yoke to the driveshaft. You may also need to have them shorten your driveshaft by a little bit, but I didn’t need to have mine shortened. It cost me $100 to have a new yoke (mine was worn out) and a new universal joint installed on my driveshaft.

Exhaust

Headers made for a small block in your year car will fit but you will need to weld in bungs for the o2 sensors. You can buy these fittings from Windsor-Fox or Mustangs Plus. You can also make your own for the fraction of the cost using two 18mm spark plug anti-fowlers from your local auto parts store. Instructions for these homemade bungs from UltraStang can be found here. I personally suggest that you don’t get long tubes if you plan on using a cable clutch, the cable is very hard to run without the risk of melting it on the headers. If you choose to use factory manifolds, you will need to weld the o2 sensor bung into the exhaust piping right behind the manifolds. You can use your existing or stock exhaust from the headers back.

Wiring
This is the reason many people choose NOT to do an EFI conversion, but it really isn’t that bad if you buy an aftermarket EFI wiring harness. Sure, you can use the harness from the donor car for a lot less than buying a new one, but it is very time consuming and the harness will need to be modified. I would suggest buying a harness from Ford Fuel Injection; this is the very best aftermarket EFI harness on the market in my opinion (and I wasn’t paid to say that). I installed mine in an hour thanks to the detailed instructions, it plugs right into your classic’s body harness, uses OEM Ford connectors, and can be modified to meet your exact needs. Another option is to send the harness from your donor car to Windsor-Fox be modified to work in your classic. Windsor-Fox also sells harnesses if you don’t already have one. Painless Performance Products also sells a harness made for the swap. You will need to use the late model coil and starter solenoid as well.

This is the EFI harness from FordFuelInjection.com it has less than 30 connections to make and I installed mine in an hour:

Mustang 5.0 EFI Wiring Harness

Fuel

Your old carburetor’s fuel system was a returnless system that ran at only about 5-6psi, the EFI system utilizes a return line and operates at a much higher psi. The fuel hose from your carb’s fuel system isn’t rated for the fuel pressure associated with the EFI fuel system, so it must be replaced. Your local auto parts store should carry it for about $4-6 a foot. You can modify your fuel sender to work with a stock or aftermarket in-tank EFI fuel pump or you can use an aftermarket inline, electric pump. I chose to use a Vortech T-rex inline pump because I didn’t want to open up my gas tank; I also ran some 5/16″ stainless steel fuel line down the passenger side of my car as the fuel supply line for the engine. Bending the stainless steel line was a bit of a pain, but it was much cheaper than if I ran braided steel hose. For your return line, you can plumb a line into the fuel sender or almost any other place in the gas tank. I chose to run mine to the fuel filler neck because, again, I didn’t want to open up my gas tank. I used the original fuel supply line from the carb’s fuel system as the return line for the EFI system; it saved me a lot of time and supplies.

This is my external in-line fuel pump, I mounted it by the exhaust hanger on the passanger side in front of the gas tank:

Mustang 5.0 Fuel Pump

Here is my fuel return line, it runs down the driver’s side of the car, into the trunk, and into the filler neck:

Mustang Fuel Return Line

Belts, Accessories, and Cooling

You have two options here: using the original v-belt set up or the modern serpentine belt set up. V-belt would allow you to use the original fan and radiator, but they aren’t hard to swap out anyway. Another reason you may want to use the v-belt set up is that your car already has A/C or powersteering and you don’t want to convert them to serpentine. However, you are upgrading everything else, why use an outdated belt set up? I haven’t used the newer A/C compressor or powersteering pump in a classic, but it can be done. The newer water pump spins the opposite way of the vintage water pump so you’ll have to use the newer radiator. I found that the newer fan and radiator fit, but it was too close for comfort for me, so I switched to an electrical fan. Depending on what accessories you do or don’t use, you may need idler pullies in order for the belt to hit every pulley the correct way. You may also have problems finding radiator hoses, but I just went to the auto parts store and walked around until I found hoses with the right bends in them and then cut them if necessary. You will also need to get a shock tower brace that clears the EFI intake manifold. I suggest the export brace from MPG Heads.

Supercharging or Turbocharging your Engine
A non-intercooled single or twin turbo set up seems rather simple, as long as you can get a hold of piping with the correct bends. Another problem you may run into is finding headers that will clear the tight space between the engine and the shock towers. Many people say that running a centrifugal supercharger on a fuel injected 5.0 in a classic Mustang is impossible due to the fact that there is very little clearance between the throttle body and the shock tower so room for a supercharger pipe would be tight. I have supercharged my 5.0 using a Powerdyne kit; however, and it is pretty straightforward. Sure, the clearance is tight, but if you remove the EGR spacer and buy some longer silicone couplers, you will have just enough room to fit the pipe from the throttle body to the supercharger. I also had to extend the hoses for the bypass valve because it was touching the shocktower. You will need to locate the battery to the trunk or to the driver’s side of the engine bay if you want any sort of room for the air filter. The supplied airbox from Powerdyne fit all right but since it was designed for a fox body, I plan on making my own airbox for a cleaner, more professional look. You may have to extend the wires to the MAF if you install a supercharger. I also suggest installing all the brackets for the supercharger before you put the engine in the car just to make it easier on yourself. Don’t forget the supporting mods associated with supercharging an engine (larger fuel pump and/or injectors, FMU, MSD ignition, etc).

Belts, Accessories, and Cooling

You have two options here: using the original v-belt set up or the modern serpentine belt set up. V-belt would allow you to use the original fan and radiator, but they aren’t hard to swap out anyway. Another reason you may want to use the v-belt set up is that your car already has A/C or powersteering and you don’t want to convert them to serpentine. However, you are upgrading everything else, why use an outdated belt set up? I haven’t used the newer A/C compressor or powersteering pump in a classic, but it can be done. The newer water pump spins the opposite way of the vintage water pump so you’ll have to use the newer radiator. I found that the newer fan and radiator fit, but it was too close for comfort for me, so I switched to an electrical fan. Depending on what accessories you do or don’t use, you may need idler pullies in order for the belt to hit every pulley the correct way. You may also have problems finding radiator hoses, but I just went to the auto parts store and walked around until I found hoses with the right bends in them and then cut them if necessary. You will also need to get a shock tower brace that clears the EFI intake manifold. I suggest the export brace from MPG Heads.

Supercharging or Turbocharging your Engine

A non-intercooled single or twin turbo set up seems rather simple, as long as you can get a hold of piping with the correct bends. Another problem you may run into is finding headers that will clear the tight space between the engine and the shock towers. Many people say that running a centrifugal supercharger on a fuel injected 5.0 in a classic Mustang is impossible due to the fact that there is very little clearance between the throttle body and the shock tower so room for a supercharger pipe would be tight. I have supercharged my 5.0 using a Powerdyne kit; however, and it is pretty straightforward. Sure, the clearance is tight, but if you remove the EGR spacer and buy some longer silicone couplers, you will have just enough room to fit the pipe from the throttle body to the supercharger. I also had to extend the hoses for the bypass valve because it was touching the shocktower. You will need to locate the battery to the trunk or to the driver’s side of the engine bay if you want any sort of room for the air filter. The supplied airbox from Powerdyne fit all right but since it was designed for a fox body, I plan on making my own airbox for a cleaner, more professional look. You may have to extend the wires to the MAF if you install a supercharger. I also suggest installing all the brackets for the supercharger before you put the engine in the car just to make it easier on yourself. Don’t forget the supporting mods associated with supercharging an engine (larger fuel pump and/or injectors, FMU, MSD ignition, etc).

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  • Dportdan

    great info, thanks for taking the time to write this.  two questions, where did you mount your computer and what is the bright red box under the hood on the driver forward panel?
    - Dan 

  • Millersj32

    Looks like a MSD Ignition control box

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  • Anonymous

    I’m dropping a ’93 5.0 into a ’67 Cougar but I am converting the new motor to carbureted. I understand the benefits of EFI but I grew up on carbs and want a shorter less expensive install. Thanks for the info on the oil pick up swap. Haven’t had the pan off of the new one yet and was worried about that. Will the original oil pan work with the ’93 block if you swap the pickup? I’ve seen ads for oil pans saying they won’t work with the 1 piece rear main on the ’93 block or something to that effect.
    Thanks for the info overall. Very helpful!

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  • http://profile.yahoo.com/ZXGHUAE2SGRDLG7MCZPVETARCE Chris

    i love this page! it has been very informative. i am currently considering to buy an 82 gt donor car with a t5 tran. for my 66 mustang coupe.   this is not my first restoration but it is my first engine swap. the 82 is not fuel injected so im hoping everything goes in smoothly. but.. my 66 has a straight six right now.  what other things might i have to buy or modify in my particular case??

  • http://profile.yahoo.com/2KUD4ATOZVJWZUNUVNRHCAERDE Gary

    Great page with lots of good tips.  My ’66 is going to be undergoing a similar treatment, sans supercharger…for now.

  • http://www.facebook.com/sariahbechtel Sariah Bechtel

    Excellent page! Thank you. Now to purchase the donor car :-)