Vehicle 1- my daily driver. 1989 E-150. Factory built with a 302, AOD, 8.8 inch rear axle, and speed density fuel injection.
Vehicle 2- my former daily driver and first van ever, 1984 E-150. Factory built with a 351 Windsor HO, C6, and a nine inch rear axle. Engine, trans, and rear axle all rebuilt with under 10k on them.
Vehicle one was purchased several years ago when the frame on vehicle 2 broke (long story). Vehicle 1 had been used by previous owners to pull a 25 foot trailer, so the rear leaf springs and motor were shot. I managed to get another 30,000 miles out of the beat 302, but it finally gave up the ghost earlier this year.
Vehicle 2 was my project van and I had already had the entire drivetrain rebuilt. However, it was cosmetically hideous and the broken frame made me decide to swap the rebuild motor into Vehicle 1.
So the initial plan was to pull the dead 302 and stick in the rebuilt 351. Since I was putting a 351 in place of a 302, I knew I needed different intake manifolds. I also knew that the 302 fuel injection computer would not work with the 351 since the firing orders are different. Further, I couldn't just plug in a 351 speed density injection computer since I was running an aftermarklet and more aggressive cam in the 84 motor. I researched and found that the solution to my problem would be top switch the fuel injection system to a mass airflow system out of an 89-93 Ford Mustang. They came with high output 302 motors. The HO 302 firing order is the same as the 351 firing order, and the mass air flow injection system can be used with aftermarket cams. Yay.
So, leaving out the gory details, I purchased a complete core fuel injected 351 out of an 89 Bronco. It had all the hard fuel injection parts- manifolds, injectors, fuel rail, wiring harness. I also purchased a complete MAF conversion kit from a guy who was going to put it on his early 60s mercury. but decided against it. The MAF parts included the computer, wiring harness, manifolds, and all sensors from a 93 Mustang GT.
Out came the 302. While the motor was out and access to the wiring harness was easy, I used the wiring harness from the Mustang and created an "overlay harness" for my van. The computers on Ford vans are tucked underneath the heater/AC fan. You unbolt the plug from the engine side and pull the computer down and in from the passenger side. It is VERY hard to get to with the van put together.
Here is the plug that goes into the computer:
I was in the middle of re-pinning it and adding some of the wires.
Two invaluable resources for this project were
www.fordfuelinjection.com and
www.ford-trucks.com All technical info for doing this swap, including wiring diagrams and how to make your own wiring harness can be found at
www.fordfuelinjection.com Ford-Trucks.com has some very knowledgeable and helpful folks who will answer your questions about this swap.
I installed the overlay harness, repinned the plug for the computer, installed the new computer, and stuck in the 351W. I bolted it all together and the motor wouldn't start.
After several weeks of troubleshooting, I tracked down the problem to my installing the distributor 180 degrees out of time. The motor would then run, but it ran like poo. I then began a several week process of eliminating trouble codes, replacing sensors and parts, and double checking everything I did. One change I had to make was to fool the computer into thinking I had two oxygen sensors. Speed density systems use one oxygen sensor on the passenger side. MAF systems use one oxygen sensor on each side. You can split the signal from the passenger side sensor and fool the computer into thinking there are two sensors. Apparently this is how Ford tells you to wire it when you purchase one of their MAF retrofit kits.
An absolutely invaluable tool for this swap is a handheld diagnostic computer. I purchased a used OTC2000 tolls and software on ebay for about $60 a few years back. This was an immense help since I could run the self-diagnostic tests with it and get trouble codes from the onboard computer in the van.
Anyhow, I got the van running OK and took it for a test drive, it wouldn't idle right, especially when cold, but I thought maybe the computer needed a test drive to learn all the parameters of the motor. I start driving and notice a hesitation in the transmission engaging in gears. As I drove, I found the transmission was slipping, and it is slowly getting worse. None of this happened before the motor swap. I get back home and discover transmission fluid pouring out of the bottom of the bellhousing. Turns out that Ford used a whackload of difference flex plates and I used the wrong one. You have to buy the flexplate for the specific engine and transmission combination. I had tried to mate a 351 to an AOD, a rare combination only offered in early 80s trucks and late 80s Crown Victorias, by using the flex plate for the C6/351 combination. Fortunately, I found a place that sells them for $25 online. Unfortunately, I found this out AFTER I had trashed my transmission.
So out came the AOD, in went the rebuilt C6 from vehicle 2. After the C6 was in place, I discovered (a) the factory 89 driveshaft was too long, and (b) the 8.8 rear axle uses a different attaching method to the driveshaft than does the nine inch axle. So then it was time to swap the rear axles so I could use the driveshaft out of vehicle 2. I left the springs bolted to the rear axle. THis made the swap much easier.
The van still wouldn't idle, but I finally tracked it down to a bad MAF sensor. People were telling me that these rarely fail and I should try cleaning it, but I DID clean it and it still wouldn't work.
So, in the end, what was going to be a simple engine swap turned into a two month long complete drivetrain swap between my vans. However, the end result is work it. I am still fine tuning a few final things, but the increased power is amazing, the idle is smooth, and the throttle response is far superior to the old motor.
So, here is a list of all the things I had to do, categorized by component:
SWAPPING 351 IN PLACE OF 302:
Engine:
The 351 bolts right in place of the 302. Transmission bell housing is the same, I believe motor mounts are the same, but I just used the 351 motor mounts
Exhuast: The 351 is a wider motor than the 302, so you will need to either have your exhaust redone or do like I did and order a new Y pipe. Summit racing sells Y pipes for Ford pickup that are a near perfect fit, but not exact. It is working so far on my van, so I'm not griping. However, sometime in the 80s, Ford changed the outlet angle on both the 302 exhaust manifolds and the 351 manifolds. Check this before ordering a y-pipe.
Transmission:
USE THE RIGHT FLEX PLATE! Don't be a dummy like me and ruin a perfectly good transmission. The flex plate must be the correct weight to match the motor and must be the correct depth to match the transmission. All this info is readily available online, so I won't repost it.
If you are using the C6 with fuel injection, you will need either the factory kickdown/TV cable for the fuel injection and C6 or you will need a Lokar-style cable. Fortunately I was already using a Lokar cable so this swap was easy.
Also, if you are swapping a C6 in place of an AOD (or vice versa), you will need to splice the wires going to the neutral start switch. The AOD and the C6 use different neutral start switches, but the wires are the same color between the two and do the same functions.
Finally, if you switch from AOD to C6 or vice-versa, you will need to adjust the shift linkage and change the gear indicator on the steering column.
Installing MAF injection:
I was ultimately going to be switching the 351 from carbureted to MAF injected. This is trickier than you would think.
First, you need the intake manifolds, fuel rail, injectors, wiring harness, and sensors from a fuel injected 351. Any injected 351 will do, so long as it bolts to your heads.
Second, you need the MAF injection system. This is essentially the engine control computer, wiring harness, and MAF sensor. The two main differences between the speed density system found in pre 93 Ford vans and the MAF system is the use of the MAF sensor to measure the actual amount of air entering the motor and the firing of the injectors sequentially rather than in two groups of four.
If you already have a fuel injected van, you are ahead of the game. The only things you will need to do is add the MAF sensor and wiring to your existing wiring harness, swap computers, add the individual wiring for the injectors, and plumb in the MAF sensor to the air intake tract.
If you have a carbureted van, you will also need to worry about fuel supply and swapping the accessories to the factory serpentine belt system. You cannot use the mechanical fuel pump from a carbureted motor in a fuel injection system. FI requires 30+ PSI to operate, but a carburetor needs 2-10 PSI. You will need to figure out a way to plumb a high pressure fuel supply as well as a fuel return to the tank. I didn't have to do this since my 89 van was already fuel injected, but it shouldn't be too hard.
The next hurdle you will have to overcome in installing MAF injection is the air intake tract. Anyone who owns or has popped the hood on a fuel injected Ford van is familiar with the big black box and two rubber hoses that dominate the space above the radiator. Note the two rubber hoses. Ford trucks and vans used a throttle body with twin small bores. Mustangs used throttle bodies with a single large bore. The throttle bodies are not interchangeable since the Mustang intakes are different form the truck intakes. This is problematic because the MAF sensor uses the single large air intake tube design to hook up to the Mustang throttle body. What is needed is a way to adapt the single MAF bore to the dual truck throttle body bores. There are several ways to do this.
Option 1 (what I did): Fordmuscle magazine has an online article where they detail switching their 302 powered 89 Ford pickup from speed density to MAF. you have to pay for the whole article, but the first page is free and tells you everything you need to know anyway. They tackled the throttle body problem by using a K&N air filter kit that adapts form the dual bore to the single bore. This looks pretty slick and is the cleanest way to go. However, the K$N kit costs over $200 new, and I couldn't find any used. The Fordmuscle article mentions a factory piece that does the same thing.
Apparently, 1995 Ford trucks with the 300 motor had a factory air intake tube the went from two bore down to one. Sounds ideal. Unfortunately, it is a one year only piece. I was able to order one of the last two in the Ford dealership inventory network. It set me back about $80, with shipping. The problem with this piece is the bores on the 300 throttle body are smaller than the bores on the 302 and 351 throttle body. The rubber hoses from the 302 throttle body fit over the plastic 300 tube but leave a big gap. Air gaps past the MAF sensor are bad since any air entering after the sensor won't be accounted for and will screw up the mixture. Additionally, the plastic on this 300 air tube isn't very stiff so you can't just crank down on some screw clamps to tighten the rubber hoses up to the plastic hose. My solution was to cut two piece of exhaust pipe and stick one in each end of the plastic tube. This gave the tube enough rigidity that I could then clamp the ends of the rubber hoses around the plastic tube and get a good seal. I also slathered the joint with RTV sealant to make sure it was air tight. Not pretty, but it works.
Next problem is the air filter. You loose the factory square air filter and box for it. A tuner cone filter from Autozone fixes this. You also loose the clean air source for the smog pump. A smaller cone air filter fixes this.
Option 2: I didn't use this option since I was using a 351. However, if you have a 302 in your van, you have a much simpler solution to the problem of the throttle body. Use the Mustang upper intake manifold. It will bolt right in on top of the fuel injected intake manifold (especially if it came from the same Mustang) and is a far lower profile than the truck/van intake so it will clear the firewall in a van. If you use the Mustang upper intake you can also use the Mustang throttle body and air intake hose. These will hook right up to the MAF sensor. The only downside to this I can think of is that Ford trucks have longer intake manifolds for a reason- to boost torque and low RPM power. In a van, you really want all the low RPM torque and power you can get. however, I can't imagine the tradeoff is enough to insist on using the truck upper intake if you don't have to.
I have heard that there were 351s stuffed into 89-93 Mustangs from the factory, but these are rare and the intake are probably expensive. If you could find a fuel injected 351 Mustang intake (or posibly from a Crown Vic or Grand Marquis or Lincoln), you might be able to use that intake and use the single bore throttle body. I don't know.
Option 3: Aftermarket. There are companies (like Edelbrock) that will sell you throttle bodies and intake manifolds that look like standard old carburetors and carbureted intake manifolds but that are drilled and prepped for fuel injection. They will also sell you injects and fuel rails. This is very expensive, so I didn't investigate this too much. I try to use functional junkyard parts in my swaps since I'm not made of money and don't have a money tree in my yard.
Keep in mind that this is all applicable to 75-up vans. if you have an early or a mid you will have other issues with doghouse clearance and air intake ducting. You really should get as close to a true cold air intake as possible, and you should carefully measure clearance, especially if you are running a 351.
Emissions equipment:
I like clean air, and I really like the ozone. For me, those are reasons enough to keep all emissions equipment intact and functioning. However, by 89, the emissions systems were also integral to the functioning of the fuel injection system. There are ways to disconnect the EGR valve and fool the computer into thinking it is there and functioning, but I didn't do that and I don't think you should either. The EGR valve improves fuel economy and emissions, so there really isn't any downside to it. The smog pump just hangs off the front of the motor and really draws very little power form the engine. Using fuel injection makes it entirely feasible to use catalytic converters since the fuel mixture is much better controlled than with a carb. Do it. My point is that you should really leave all emissions systems intact and functioning on a carbureted vehicle.
EGR valve considerations:
On the fuel injected 302, the EGR valve draws exhaust gases from the lower intake manifold. On the 351, the EGR valve draws the exhaust gases from the passenger side exhaust manifold. Swapping a carbureted 302 to MAF injection is therefore simpler in that you can keep the EGR by just swapping intakes, something you have to do anyway. On 351s you also have to make sure your passenger side exhaust manifold has the provision for the EGR. Napa sells new passenger exhaust manifolds with the right port for $110. you can also buy headers. I bought a set of Pacemaker headers from Summit with the EGR provision for about $150. There didn't fit and interfered with the doghouse, and it would have been impossible to change the spark plugs with the manifold installed. Fortunately, the 351 parts motor I bought had some unknown brand of headers on it that someone had welded the EGR port onto. Yay. These clear the doghouse and offer MUCH better access to the spark plugs.
Accessories:
Swapping to MAF also requires swapping to the factory serpentine belt setup, mainly because of the smog pump. You also will need to get a blockoff plate for the old mechanical fuel pump or change timing chain covers. I switched to the serpentine belt setup and switched to the timing chain cover off of the fuel injected parts motor.
Ignition:
You will need the ignition system from the fuel injected vehicle. The distributor, the TFI module bolted to the distributor, the coil, and all the wiring. The distributor tells the computer when cylinder 1 is firing, and the computer uses this signal to calibrate other things. The factory coil is much better than the older coils used on carbureted vehicles as well.
If you already have a SD motor, then you are fine. You only need a new distributor and ignition system if you are switching from carburetion to fuel injection. It isn't really that hard, its just a few more pieces to buy.
So, that's it. I went from a van with a speed density injected 302/AOD/8.8 inch rear axle drivetrain to a van with a MAF injected 351WH.O./C6/9 inch drivetrain. I am sad about losing the overdrive, but I have all the parts I need to put the AOD back in after it gets rebuilt. The increased power of the 351 over the 302 is incredible, and the MAF is much better than the SD system. I am anxious to see how my MPG is now.
If I were to do this swap again, I think I would try and use the intake manifolds off of a Mustang for a 302 or a Grand Marquis or Lincoln for the 351. This would greatly simplify the installation of the air intake tract and let you use a better air filter. I am running a cheesy "Specter" brand cone filter. Yuck. Further, if I was doing this swap in a mid or early Ford where space under the doghouse is at a premium and the air intake options are more limited, using the passenger car intake manifolds would give you a lower profile intake and let you use factory air intake tube or use a wide variety of aftermarket intake tubes.
Feel free to ask me any questions. I am sure I have left out details. I will also post some pictures once I get around to it. Right now I am letting my back and hands heal after this ordeal. I have some wiring diagrams and repinning diagrams that made my swap MUCH simpler, and I would be happy to share them.