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Something Spiffy
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Discussion Starter #1
this is a write-up that i did alittle while ago, tell me what you guys think, tell me what you think, any corrections?





Now I have noticed that there have been a lot of questions retaining to what is needed to swap from an I6 and a 302 to a 351. Since I have not seen that anyone has wrote up about this, I thought heck why not me! To be honest. The engine swap started out as a college student with a bronco that housed a bad 302EFI motor. I had bought the truck to only later realize that while the 302 is a very dependable motor, it is not impressive to show off to friends and does feel kind of under powered for the size vehicle. Because I had not thought of this before, I do not have any real good photos of the swap, just some minor ones. I will try and be in good detail about what works.
Note...keep in mind that I might forget some things or accidentally leave some things out, ill try to do my best with noting all the things I have found out. But some of your own personal research should be done.
Step 1. The research!
To start off with, I think that it is worth mentioning that if your engine is bad, but still drives well, find the replacement motor first! I had got a little carried away with taking it apart while I wish I had a car to drive to find parts! Let¡¦s start off with the basics parts. There are only a handful of parts that need to be changed if you are starting with the 302. But if you are starting with the big six, it would be a good idea to buy a new radiator, you don¡¦t have to, but in my opinion, a single row radiator is a bad idea on 351.
302 to 351:
„h Allot of people recommend getting a 351 wire harness when you get an engine. With my bad luck, never found one and used my 302 harness with little modification.
„h 351 EEC IV, I found this to be a must! I have talked to people about this online, and with local ford performance shops. The information that I found was that it might run rich, and some would say that it would run lean. Either way you are running a risk. I have also herd that if you are coming from a MAF system, that there is noting to worry about. But Don¡¦t Hold ME to it!
„h A/C and power steering pump bracket. This is needed due to the 351 being much wider than the 302. Due to my 302 being from an 87 and my 351 being from a 90¡¦s F150, I had to jimmy up my 302 bracket to work. The reason that I did that is because of my A/C pump. It bolts up completely differently than the bracket with the engine came with (look at pic below). I will later be draining my A/C system, Buy a new pump with the right bracket mounts, and swap steering pump to other bracket for the 351 soon.
„h IF your 302FI is older than 87, then you will also need to convert your power steering, A/C pump, and your alternator over to a serpentine belt system. Once again I do not know much on this because I was lucky that I already had a serpentine belt system.
„h You will also need a new exhaust system, I have been told that you can just cut the y-pipe of your truck and put a spacer in it for it to bolt up to your exhaust manifolds. It just did not look like it would work, so I went to my true duel Flowmaster exhaust instead!
„h MAKE SHURE TO GET THE RIGHT FLEXPLATE!!! When I did my swap I used a 351 flexplate that was made for the E4OD or the C6, it sticks out too far and it fried my trans when I tried to drive it. A good way to go is to compare the flywheel that came off of the old engine with the new one and make shure that they are the currect tooth, size and depth.

When considering this swap, you probably already know this, but it is a good idea to get a crate motor with fuel injection or a junkyard motor. It is nice because it will often come with most of the parts needed like the oil pan, fuel rails injectors and etc. I think that it is worth mentioning, if you are putting a carbed motor in your truck, you must not use any electronic controls on the engine like high-pressure fuel pump and EFI distributor.

If you are swapping from an I6, I think it¡¦s the same thing as the points given up above with the 302. But you will also need to get V8 motor mounts to swap in place of your I6 mounts. There is also allot of re-wiring to do if you choose to use the original wire harness.

Step 2, The swap!
The swap was overall really simple once you figure out how to wire the beast up! The Hayne¡¦s Manual covers this swap very well. It was really strait forward.
„h Disconnect all wiring from engine (remove upper intake to access the injector wiring)
„h Drain the coolant and remove the radiator.
„h Drain the engine oil and remove the oil filter.
„h Disconnect fuel lines (requires a special removal tool that is easily found)
„h Remove starter
„h Remove flex plate cover and rotate the engine to remove the Torque converter-to-engine bolts (note, be sure to rotate the engine clock wise when looking at it from the front)
„h Unbolt the exhaust manifolds.
„h Unbolt the A/C compressor and tie it off to the side
„h Unbolt the Power steering pump bracket and tie that with the pump on it off to the side.
„h Unbolt the engine mounts and raise the engine up about an inch with a shop crane and then unbolt the transmission to engine bolts. It helps to remove the access plate inside the cab under the carpet for these bolts
And with some shaking, the engine should come up and out!
Once again I was being brief with the removal of the engine, Just get yourself a Hayne¡¦s manual and it will tell you in much better detail how it is removed.

Getting the engine in and bolted up to the transmission was hard for me, I had ended up unbolting the motor mounts to get a better angle at the time. The 351 does not seem all that much bigger until you place it in where the 302 sat!

To attach the motor to the Trans you need to get the motor completely lined up, up to the point where you can almost bolt it up. You will then pull the torque converter out a little bit so you can attach the torque converter to flexplate bolts (Do not use these bolts to align up the engine!). Once that is attached, carefully slide the engine to the Trans and bolt it up. Then if you did what I did you will raise the engine a little and attach the motor mounts. The rest of the installation is the same as you had taken it out.

If you are using a fresh crate motor, you will want to remove the sparkplugs and crank to motor untill you read oilpress on your gauge. It is a good idea to get a set of mechanical gauges to make shure that it is oporating at the right temp and that it has the currect oil press. When you start the motor for the first time, first check the oil press gauge to make shure that it is alright, then go over to the upper radiator hose and check to feel if coolant starts flowing once it is warmed up. Once you are shure it has good oil press and that the thermostat is working properly and not over heating, take it for a test drive. The Hayne¡¦s manual says to also have your A/C system recharged and checked for leaks.
 

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damn, my mechanic told me this was all but undoable when my 302 blew. I put another 302 in due to his advise.

o well.
 

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Something Spiffy
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940 Posts
Discussion Starter #6
njbuck said:
damn, my mechanic told me this was all but undoable when my 302 blew. I put another 302 in due to his advise.

o well.
i remember back in the day when i was told the same thing. funny, now that i think about it i was also told around that time that I should not install my own lift kit. lol i have come a long way...
 

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The Anti Yam!
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njbuck said:
damn, my mechanic told me this was all but undoable when my 302 blew
Fire your mechanic


njbuck said:
Do the motor mounts line up?
Yes
 

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now of course I realize the crate prices start at a few hundred more than I paid for the rebuilt 302 :banghead

now, if I kill him.. I still go to jail right? :toothless
 

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Something Spiffy
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940 Posts
Discussion Starter #11
njbuck said:
now of course I realize the crate prices start at a few hundred more than I paid for the rebuilt 302 :banghead

now, if I kill him.. I still go to jail right? :toothless
its funny though, i was told the same thing awhile back by a Mustang performance shop. i almost gave up but then i got the response i wanted out of some guys off of FTE. it has yet to feel like i have the motor running at its full potential, but i strongly think its because my wire harness that i re-used from the 302 is fried somewhere thus being very diffacult to diagnose.
 

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Premium Member
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So now if I needed to swap out my 351w. Which way would you guys advice? Another 351w, 460, or 4bt? Cost is a factor here and I've never done a swap before.
 

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Beach bumming it ........
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So now if I needed to swap out my 351w. Which way would you guys advice? Another 351w, 460, or 4bt? Cost is a factor here and I've never done a swap before.
I would stick with another 351w EFI it will be less work on your part and cheaper. If you want to swap a 460 EFI in you would want to have some cash and time saved up. I would never recommend taking a FI vehicle and making it Carbed.
 

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aka: kemicalburns
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7,796 Posts
drop another 5.8 in there. heck look for another complete 5.8 from another wrecked 96 with low miles and drop it right in and drive off. you could sell your current motor for a decent amount to offset the cost. the roller 5.8 blocks can fetch a couple hundred if they are rebuildable still.
 
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