[JC316]

This is a step by step guide for swapping a Mark VIII engine in your Mustang GT. This is a cheap, but labor intensive project. I give this as a high difficulty rating. You need to have a quality tool set, a lot of patience, and a good knowledge of mechanics. If you can change a head gasket, or rebuild a motor, you should be able to do this swap. If I have to tell you when to jack the car up, or explain how to remove the old engine, then this swap is not for you. The pictures are going to be in URL format for a clean post.

Parts that are absolutely needed:
97-98 Mark VIII engine, complete with vacuum lines.
97-98 Mark VIII Throttle Cable
97-98 Mark VIII Upper fuel lines. * These disconnect in the passenger side wheel well of the Lincoln.
93-98 Mark VIII thermostat housing
93-98 Mark VIII Alternator
96+ Mustang GT wiring harness.
96+ Mustang GT oil pan and pickup tube
96-01 Mustang Cobra Exhaust manifolds. * I prefer the 99+ because they don't have the air injection system that the 96-98 does.
96-? Mustang GT Coolant sensors.
96-01 Mustang Cobra water hoses.

* Manual transmission only parts
96-? Mustang GT 6 bolt flywheel
96-? Mustang GT clutch.
96-98 Mustang GT Pilot bearing.

Tools required:

2 floor jacks
2 Jackstands
A set of car ramps.
Multiple extensions and swivels
A decent socket set with at least one 8, 10, 13, 15, and 18MM socket
A decent set of wrenches with at least one 8, 10, 13, 15, and 18MM. And one 7/8th's wrench for the motor mount bolts. I recommend having at least two 10, 13, and 15MM wrenches.
A decent screwdriver set
A mustang Haynes manual.



Step 1. Remove the old 2V engine. This can be done in several ways, so pick your poison. I took mine out the top, leaving the transmission in the car. I deem this a mistake since I couldn't get the clearance required to reinstall the 4V engine and I had to remove the transmission and lower the K member to reinstall. You can leave the power steering pump and the A/C compressor in the engine bay and still hooked up as you will be reusing them on the new engine.
http://i108.photobucket.com/albums/n...d/SDC14321.jpg
http://i108.photobucket.com/albums/n...d/SDC14327.jpg

Step 2. Locate a Mark VIII engine. I have heard that the Gen 1 93-96 motors will work, including the intake, but I can't confirm. I found a 97 engine, which has an intake more like the Cobra does and will work fine. The heads on the 97 are also superior to the 93-95 engines. They use a beehive valve spring and the valves are not shrouded.
http://i108.photobucket.com/albums/n...SDC14337-1.jpg
http://i108.photobucket.com/albums/n...SDC14338-1.jpg

Step 3. Remove the wiring harness from the 2V engine. Be SURE to take pictures of everything, so you can remember where everything goes.
http://i108.photobucket.com/albums/n...d/SDC14339.jpg

Step 4. Swap the oil pan and pickup tube from the 2V motor to the 4V motor. Also install the cobra manifolds and the motor mounts at this time. You can bolt the mounts to the K member, but I don't recommend it. It's a pain to get them attached once the motor is in and I had to grind the edge down to fit on the passenger side. The dipstick tube will have to be bent slightly to install the motor mount on the drivers side.

Step 5. Install the wiring harness on the 4V engine. Be sure to start with the fuel injector connectors and work from there. You will have to cut and splice several wires. These wires are the Idle air control, the EGR sensor, camshaft position sensor, and the two coolant sensor wires. * Note, the 4V engine uses knock sensors, the wire comes out from under the intake on the rear of the motor, I chose to stuff the wires under the intake. You will also have to thread the second coolant sensor from the GT in at this time.

Step 5B. Vacuum lines.
The Mark VIII uses a vacuum brake booster, you will need to cap this line first, it's on the back of the engine and is the larger port back there. You can delete the line going to the air injection system. Run the PCV valve to one of the ports on top of the intake, then cap the other one. Take the EGR flow sensor from the GT and run your hoses exactly like the GT would. The one coming over from the EVAP canister goes right under throttle body, there is a line under there.

Step 6. EGR and IMRC's. If you are keeping them both, read on, if you are deleting the EGR, but not the IMRC, skip to 6B.

Step 6 A: EGR.
If you are keeping it, you have a problem. The pipe that the Mark VIII uses is larger than the GT/Cobra uses, so it will attach to the EGR, but not the exhaust manifold. I took the GT pipe, on the manifold side and cut it in the straight section, then took the Mark VIII pipe and did the same. I then welded them together to make one pipe with the Mark VIII end attaching to the EGR and the GT end attaching to the exhaust manifold. You will have to relocate the IMRC motor and bracket to install the pipe.

Step 6 B IMRC's
You can get a delete plate, or you can keep them, or you can wire them open. Either way, you are going to have to remove or relocate the IMRC motor. I removed the motor from it's bracket, then cut the bracket in half, leaving the EGR sensor attached to the block. The IMRC motor can be relocated to the passenger valve cover.
http://i108.photobucket.com/albums/n...d/SDC14635.jpg
http://i108.photobucket.com/albums/n...d/SDC14634.jpg

Step 7. If you are using a manual transmission, bolt your flywheel and clutch to the 4v engine now. Be sure to install a new pilot bearing on the 4v engine.
http://i108.photobucket.com/albums/n...d/SDC14637.jpg

Step 8. Prepare to install the motor in the body. Install the new throttle cable BEFORE installing the engine. * If you kept the EGR, you will have to cut a section of the strut brace on the firewall side, this is necessary to clear the EGR pipe.*

Installing the motor extremely tough to do with the K member and/or the transmission still in the car. It is IMPOSSIBLE to install this motor with the K member bolted in and the transmission still in the car. I had to unbolt the transmission and lower/slide it out of the way, then mount the engine on the K member. Then I had to set the car on the ramps, unbolt the K member and lift the body up enough to bolt the transmission to the engine. *I also believe that it will be near impossible to install the engine with the transmission bolted to it due to clearance issues, but I can not confirm this*
http://i108.photobucket.com/albums/n...d/SDC14644.jpg
http://i108.photobucket.com/albums/n...d/SDC14645.jpg

Step 9. Remove the old fuel lines from their quick disconnects in the passenger fender well. Attach the Gen 2 lines to the fuel rails, then cut them off over by the old lines. Then attach a section of 5/16'ths fuel injector hose and clamp it tight to both lines on both ends.
http://i108.photobucket.com/albums/n...d/SDC14646.jpg


Step 10. Cooling system. You will have to bend the heater pipes on the motor out of the way of the heater core lines. I heated them up with a small torch and used a large punch inside the tube for leverage. It's tricky to get the radiator hoses done correctly. You should get Cobra hoses, but you CAN do it with the GT stuff, but it takes a lot of fabrication and I am still unsure about the quality of this, so just get the cobra hoses.


Step 11. Tune. The stock GT computer WILL control this engine fine, it's 100% confirmed. I have 400+ miles on it with absolutely no problems or check engine lights. I am going to get it tuned later on because I am sure that I am leaving power on the table, but the GT computer will control the motor just fine with it completely stock.

The final result looks a little something like this:
http://i108.photobucket.com/albums/n...s/SDC14752.jpg

Here are a few videos of the car completed.

4V rebuild :: SDC14647.flv video by JC316_2006 -...

YouTube - 1996 Mustang GT with Mark VIII 4V...

YouTube - 96 Mustang GT 4V walkaround

[97GT4.6]

Great writeup! This needs to be stickied.

[JC316]

Originally Posted by 97GT4.6 Great writeup! This needs to be stickied.

Thanks. I put a lot of time and work into the car and the guide. As far as I know, there is no other guide like it.

[Mont96GT]

Why wasn't your temp gauge working?

[JC316]

Originally Posted by Mont96GT Why wasn't your temp gauge working?

Because I didn't take my own advice and thread in the temperature sensor yet. I was using a code reader with live data to monitor the temperature.

[G.T. Rags]

nice write up man..... reps

[330CubeGt]

Nice Write up...

[UWISHU1]

pretty sweet swap, would work great in my 95 T-bird

[JC316]

Originally Posted by UWISHU1 pretty sweet swap, would work great in my 95 T-bird

Yeah, it would. I have seen a couple of swaps like this in a T-bird or Cougar. Not sure about the computer though since the 95 is still OBD1.

[ForestGRN_Ghost]

Step 5. Install the wiring harness on the 4V engine. Be sure to start with the fuel injector connectors and work from there. You will have to cut and splice several wires. These wires are the Idle air control, the EGR sensor, camshaft position sensor, and the two coolant sensor wires. * Note, the 4V engine uses knock sensors, the wire comes out from under the intake on the rear of the motor, I chose to stuff the wires under the intake. You will also have to thread the second coolant sensor from the GT in at this time.



sooo... what did you do about the knock sensor.?

[ForestGRN_Ghost]

all you said was the 4v has a knock sensor. and you stuffed it under the intake ?

im just curious.

[JC316]

Originally Posted by ForestGRN_Ghost Step 5. Install the wiring harness on the 4V engine. Be sure to start with the fuel injector connectors and work from there. You will have to cut and splice several wires. These wires are the Idle air control, the EGR sensor, camshaft position sensor, and the two coolant sensor wires. * Note, the 4V engine uses knock sensors, the wire comes out from under the intake on the rear of the motor, I chose to stuff the wires under the intake. You will also have to thread the second coolant sensor from the GT in at this time. sooo... what did you do about the knock sensor.?

Nothing, I just stuffed the wires under the intake. You don't hook it up with the GT computer. I consulted several experts on this and I was assured that it would be safe.

[ForestGRN_Ghost]

lol if it works it works.
but if you have the mark wireing harness.
why not use it ?

there is a guy were i live that has a 97 mark 8
for sale. the motor is straight but the tranny is blown
and the seats all all f'd up. but i mean i olny want the motor.
so would it be better for me to just use that harness
or keep with my gt harness

[JC316]

Originally Posted by ForestGRN_Ghost lol if it works it works. but if you have the mark wireing harness. why not use it ? there is a guy were i live that has a 97 mark 8 for sale. the motor is straight but the tranny is blown and the seats all all f'd up. but i mean i olny want the motor. so would it be better for me to just use that harness or keep with my gt harness

GT harness is the easiest/most effective method. There is a bunch of other crap that goes with the Mark VIII harness, it doesn't even hook up the same way.

You will love the motor if you do the swap. It's better in every way from what I have experienced.

[98FireyGT]

Ghost hurry up and buy it! I wanna do that PI Swap dammit.

[dcook_14]

I'm confused how you can use exhaust manifolds from a 99/01 cobra on this since they have C heads and the Mark VIII has B heads. Unless the exhaust ports on the heads are the same and it's just the swirl vs. tumble intake ports that make the heads different.

Also, how does the GT Computer control the IMRC system?

[JC316]

Originally Posted by dcook_14 I'm confused how you can use exhaust manifolds from a 99/01 cobra on this since they have C heads and the Mark VIII has B heads. Unless the exhaust ports on the heads are the same and it's just the swirl vs. tumble intake ports that make the heads different. Also, how does the GT Computer control the IMRC system?

The C heads have the same exhaust ports as the B head. I was lucky enough to find a guy that was local so I could compare. The GT computer wont control the IMRC's. You have to wire up a RPM window switch to the electric motor if you want to keep them.

[01midnightstang]

Ok, so i have a chance to get a 96 mark motor or a 98 mark motor, the question i have is, is there a difference between the two engines? the 96 is 350 and the 98 is 500 and they both have 100,000 miles and the price difference is why im asking. I plan to put a 03-04 cobra intake and supercharger on it so i dont much care about the intake? Let me know

[JC316]

Originally Posted by 01midnightstang Ok, so i have a chance to get a 96 mark motor or a 98 mark motor, the question i have is, is there a difference between the two engines? the 96 is 350 and the 98 is 500 and they both have 100,000 miles and the price difference is why im asking. I plan to put a 03-04 cobra intake and supercharger on it so i dont much care about the intake? Let me know

Then nothing. The 96 has the beehive valve springs and the unshrouded valves. The only difference is the intake and the IMRC's are vacuum.

[drazga97]

wow nice write up reps