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Thread: 5.0L swap questions.

  1. #1
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    Oct 2011
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    5.0L swap questions.

    First off, let me say that I did search and all I came up with is a bunch of people asking how to do it and a bunch of people telling them not to do it. Please don't tell me to just get a V8 since I have worked my butt off getting this car the way I like it.

    10K after a rebuild, my SC started knocking and I am done with the 3.8L engine. Ideally, I would go with a 5.3L LSx, but I cant afford a T56 and an automatic flat isn't an option. So I am looking at swapping in a 5.0L. They are so much cheaper and easier than the 3.8L. I intend on using the M5R2 transmission that is in it now.

    From what I gather, the engine will drop in place fine, I will need an F150 flywheel/clutch and starter. My biggest question is about the wiring harness. I know that I will be needing the engine wiring harness off from whatever I am getting, but what about the dash harness and ECM? I want all of my SC stuff to work, right down to the check engine light, so how would I go about that?

  2. #2
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    I looked into the engine harness for swapping a 4.6 into a 3.8 car and the wiring seemed very do able. If it was me, get a complete engine harness and the harness from the engine compartment to the ECM. You will probably have to re-pin the existing 3.8 harness to add the missing wires and swap some around for different sensors. I will look at my wiring diagram and see about a 5.0 swap. just to make sure.

    Mark

  3. #3
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    It will somewhat depend on what year your car is, and what year the donor 5.0HO comes from.

    Ideally, you'd find a 5.0HO complete donor car, and use the necessary parts off of it.

    Don't forget you'll also need the motor mounts off a 91-93 TBird/Cougar. Or a set of mounts from TurboChuck.

    I'd also HIGHLY recommend the EVTM for the year(s) in question. Helm has them ( www.helminc.com ) or you can usually find them on eBay.

    RwP

  4. #4
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    Quote Originally Posted by RalphP View Post
    It will somewhat depend on what year your car is, and what year the donor 5.0HO comes from.

    Ideally, you'd find a 5.0HO complete donor car, and use the necessary parts off of it.

    Don't forget you'll also need the motor mounts off a 91-93 TBird/Cougar. Or a set of mounts from TurboChuck.

    I'd also HIGHLY recommend the EVTM for the year(s) in question. Helm has them ( www.helminc.com ) or you can usually find them on eBay.

    RwP
    Sorry, it's a 1992. I have a ton of pick N pulls near me, so I can get anything that I need, off pretty much any year. Also, the intake isn't going to make much difference because I have a Cervinis hood that adds a good amount of clearance. So ideally, it would be out of a Mustang GT, or a Mark VII.

  5. #5
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    One reason for getting a 91-93 MN12 donor is that all the wiring is native to the MN12 chassis. The wiring harnesses may, or may not, be identical on the others.

    The reason to pick up a rolling donor car is so that any and all parts you need will be on there.

    Ideally you'd find a rusted out hulk that was tail ended too badly.

    But that's ideal The 94-95 GT uses the same intake and accessory brackets as the 91-93 MN12 did on the 5.0HO, so there's no big advantage from using one of those.

    But again, I'd grab the EVTM for your car, and for the donor if possible. If the donor is a 1992, then that will save you $22.50 or so from Helm (see http://www.helminc.com/helm/Result.a...elected_media= for the books they have available for a 1992.)

    When you pull the motor, get the motor harness. If the donor is a MN12, grab the ECM also. And if possible, the dash harnesses.

    Better to have one you don't need then need one you don't have.

    I'd plan on doing a rebuild of the 5.0HO before you drop it in - nothing drastic, just a freshen up (head touchup, or if you're feeling your oats, maybe a GT40 head set; if you're planning on a QuarterHorse, a bigger set of injectors; replace all sensors; etc. etc.)

    You may find better info on this at the "evil cousin" website, forums.tccoa.com Where everyone knows your name and there's a metric boatload of V8 owners to help.

    RwP

  6. #6
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    You won't get the kind of help you need at TCCOA because those guys are starting with V8's and wont' be able to tell you how to swap it over.

    I've swapped several SC's to V8 so I do know what is involved to do it successfully while maintaining all your SC functionality.

    1) You'll need 5.0 Tbird, and don't get a rusted out one. Get one that is clean because the last thing you want is a bunch of corroded parts.

    2) Since yours is a 92, I recommend a 92/3 donor car but a 91 will work too. If you get a 91 then the motor mounts won't fit and you'll need to get some aftermarket ones made. Chuck can hook you up with those. Keep in mind it's not the rubber mount that you need so much as it is the brackets. You can't buy new brackets so you need the right ones or you'll need some custom.

    3) There are many reasons not to use a Fox body 5.0. There are many things different that I'm not going to get into. You can either trust me on this or try to wing it on your own with stuff that doesn't fit. If you want a total hot rod then by all means go ahead with the Fox 5.0. If you want to build the car the way Ford would have done it then you'll need the Tbird 5.0.

    4) Expect the 5.0 to be slower than an SC. Even with a 347 stroker kit and heads/cam it will still seem slow. You'll have to turbocharge/supercharge it to pull ahead of your average lightly modded Supercoupe. Just keep that in mind with your overall plan.

    5) As for the wiring, there are only a couple very minor changes required to run the 5.0. You will have to change the entire engine wiring harness but fortunately for you in that year they basically plug right in. You'll need the gauge cluster from the 5.0 to make the tach work properly. If the donor is a 91 then you'll have to just use the tach with some modification because the cluster won't plug in (well it won't work properly because the pins are different on the 91 vs. the 92-3 which are the same fortunately).

    6) You'll have to use some of the driverside wiring harness from the 5.0 because the SC and 5.0 use different feed wiring for the IRCM. It's minor, but you have to move the EEC relay.

    7) You'll need all the AC lines and Power steering lines from the 5.0 car since those are in different locations on the two cars. And of course you'll want the radiator from the 5.0 car because it's totally different. I prefer to use an electric fan though because the clutch fan on the 5.0 cars sucks and it takes up a ton of room at the front of the motor and makes it a ~~~~ to do anything up there.

    8) You'll also need the exhaust headers from the 5.0 t-bird. No one makes headers for the swap so you'll need to deal with that. In the beginning when you are just hooking everything up and getting it to work I recommend staying with the stock exhaust (or whatever you have on there now. The 5.0 will bolt up to stock SC exhaust. I know you won't be keeping it like that, but just to get things working it will help you out.

    I have documentation on the wiring swaps somewhere but it's been a few years so I'd have to dig it out.
    Last edited by XR7 Dave; 01-14-2012 at 10:08 AM.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

  7. #7
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    Definitely get a 5.0 91-93 tbird or cougar donor car. It will make the swap so much easier because you won't have to re-engineer anything, and if you find yourself needing any small parts, they are right there on the car. Since your car is a 92, that will make everything direct bolt-in swap. As far as the motor mount issue goes, the upper plates are the same for all the 91-93 5.0 MN12s, only the lowers are different, but you can use your 3.8 mounts and lower brackets with the 5.0 upper brackets, so any year donor car will work. The dash harness wiring is the same for 91-93 regardless of what engine it came with, so everything should be plug and play. Putting a 5.0 into an 89/90 car is more involved as far as getting all the wiring to work. I would double check the connector views and wiring diagrams for both the 92SC and whatever donor car you get just to be sure, but it should all plug together and work fine.

    The F150 starter and flywheel is one way to do it, but another option is to get your SC flywheel rebalanced to the 5.0s 50oz imbalance, and then you can reuse your stock SC starter.

    As far as headers, the MAC 1-5/8 longtubes for a fox body mustang will work. There is a sticky in the 5.0 section of TCCoA with part numbers and slight mods needed to make them work.

    Also as Dave said, the 5.0 will FEEL a lot slower than a mildly modded SC. With H/C/I on the 5.0, it will make more HP, but the torque will be way down compared to the SC motor, and that is what makes these cars so much fun to drive. Having the 5-speed will help with that, but if you are going to do the 5.0 swap, get some AFR 165s or Trick Flow Twisted Wedges, a better cam, and a decent intake manifold and swap the motor in that way, otherwise it will be a serious disappointment when you are done. Oh, also keep an eye out for a 94/95 5-speed trans, because with the more narrow powerband of a 5.0 compared to an SC, that huge drop in rpms from 2nd to 3rd gets real old real fast. The later trans has closer ratios for 1st through 3rd, which will help keep the 5.0 engine in its powerband better.

  8. #8
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    I did the 5.0 swap on a 93 tbird and didn't like it. Engine runs great, but doesn't have the power that I was used to compared to the SC 3.8
    I'm selling the engine with harness if you need it, but I'm keeping the rolling chassis for extra parts for my SC. Engine came from a 92 mustang; rebuilt before installing and has 40k miles

  9. #9
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    If you insist on using a Mustang engine, the 94-95 5.0 is very similar to the Tbird and will already be set up for using an electric cooling fan. BTW, Dave did the 5.0 swap on my 93 SC, but by the time I was done upgrading stuff very few of parts from the swap are still on the car.

    I mention that, because if your goal is a 700 rwhp turbocharged bruiser, your better off starting with an aftermarket block based race motor, than doing the 5.0 swap. If your going to be content with 400-450 rwhp then the t-bird motor swap is the way to go.

    David
    1991 SC AOD 4.2..2.3 Whipple..........10.910 @ 125.61
    2016 SRT Challenger Hellcat...............707HP/650TQ

    My Garage

  10. #10
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    Quote Originally Posted by XR7 Dave View Post
    You won't get the kind of help you need at TCCOA because those guys are starting with V8's and wont' be able to tell you how to swap it over.

    I've swapped several SC's to V8 so I do know what is involved to do it successfully while maintaining all your SC functionality.

    1) You'll need 5.0 Tbird, and don't get a rusted out one. Get one that is clean because the last thing you want is a bunch of corroded parts.

    2) Since yours is a 92, I recommend a 92/3 donor car but a 91 will work too. If you get a 91 then the motor mounts won't fit and you'll need to get some aftermarket ones made. Chuck can hook you up with those. Keep in mind it's not the rubber mount that you need so much as it is the brackets. You can't buy new brackets so you need the right ones or you'll need some custom.

    3) There are many reasons not to use a Fox body 5.0. There are many things different that I'm not going to get into. You can either trust me on this or try to wing it on your own with stuff that doesn't fit. If you want a total hot rod then by all means go ahead with the Fox 5.0. If you want to build the car the way Ford would have done it then you'll need the Tbird 5.0.

    4) Expect the 5.0 to be slower than an SC. Even with a 347 stroker kit and heads/cam it will still seem slow. You'll have to turbocharge/supercharge it to pull ahead of your average lightly modded Supercoupe. Just keep that in mind with your overall plan.

    5) As for the wiring, there are only a couple very minor changes required to run the 5.0. You will have to change the entire engine wiring harness but fortunately for you in that year they basically plug right in. You'll need the gauge cluster from the 5.0 to make the tach work properly. If the donor is a 91 then you'll have to just use the tach with some modification because the cluster won't plug in (well it won't work properly because the pins are different on the 91 vs. the 92-3 which are the same fortunately).

    6) You'll have to use some of the driverside wiring harness from the 5.0 because the SC and 5.0 use different feed wiring for the IRCM. It's minor, but you have to move the EEC relay.

    7) You'll need all the AC lines and Power steering lines from the 5.0 car since those are in different locations on the two cars. And of course you'll want the radiator from the 5.0 car because it's totally different. I prefer to use an electric fan though because the clutch fan on the 5.0 cars sucks and it takes up a ton of room at the front of the motor and makes it a ~~~~ to do anything up there.

    8) You'll also need the exhaust headers from the 5.0 t-bird. No one makes headers for the swap so you'll need to deal with that. In the beginning when you are just hooking everything up and getting it to work I recommend staying with the stock exhaust (or whatever you have on there now. The 5.0 will bolt up to stock SC exhaust. I know you won't be keeping it like that, but just to get things working it will help you out.

    I have documentation on the wiring swaps somewhere but it's been a few years so I'd have to dig it out.
    Yes, this is the type of info that I was looking for. Thank you.

    I am not all that concerned with power, but even if I am, the 5.0 is pretty cheap to build. On a typical day, I never even get into the boost on my SC. What I figure to do is get a set of GT40P heads, aftermarket intake, and maybe a small cam. I came from a 4V mustang, which had 0 power under 3K RPM, so I understand bandwidth lag, worst case I get some 3.73's out back to compensate. At least the 5.0 redlines at 5500RPM, 1st gear is too short with the M5R2. This 3.8L is pissing me off because it's expensive to repair, requires premium fuel, and from my experience is unreliable. Not to mention that it's a ~~~~ to work on.

    I have a 3" exhaust, high flow cats, and magnaflow resonator on the SC now, so I should be set for exhaust.

    Electric fan is a must, I despise mechanical fans.

    I really want to keep the stock gauges, but I have a pillar pod that is doing nothing that I can stick a tach in.

    So, the 3.8L ECM will control the 5.0L?

    If I rebalance the stock flywheel, I can reuse the clutch that is in it correct?

    Thanks guys, I am sorry if I am full of questions, but I have done engine swaps like this before and I know to ask a ton of questions before I get started.

  11. #11
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    You will need the 5.0 tbird ecm and engine harness, but it will bolt in place and hook to your existing dash harness just fine. And yes, if you rebalance the SC flywheel, you can re-use your existing clutch if it is in good shape. Stay away from the GT40P heads in these cars. The different angle of the spark plug means that there are no headers that work with those heads and our cars. Regular GT40 heads will bolt on just fine, but will be severely lacking in power for such a heavy car, and by the time you buy a used set and have any necessary machine work done, you are spending almost as much money as buying a good condition set of used aluminum heads. Like I said before, keep an eye out for a set of AFR 165s or Trick Flow twisted wedges, or something comparable. Sign up on corral.net and stangnet.com and browse the classifieds there, and a lot of times you can find the mustang guys upgrading to bigger heads, and you can pick up a good used set of aluminum heads for around $6-700 shipped.

  12. #12
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    Quote Originally Posted by MadMikeyL View Post
    You will need the 5.0 tbird ecm and engine harness, but it will bolt in place and hook to your existing dash harness just fine. And yes, if you rebalance the SC flywheel, you can re-use your existing clutch if it is in good shape. Stay away from the GT40P heads in these cars. The different angle of the spark plug means that there are no headers that work with those heads and our cars. Regular GT40 heads will bolt on just fine, but will be severely lacking in power for such a heavy car, and by the time you buy a used set and have any necessary machine work done, you are spending almost as much money as buying a good condition set of used aluminum heads. Like I said before, keep an eye out for a set of AFR 165s or Trick Flow twisted wedges, or something comparable. Sign up on corral.net and stangnet.com and browse the classifieds there, and a lot of times you can find the mustang guys upgrading to bigger heads, and you can pick up a good used set of aluminum heads for around $6-700 shipped.
    $600 or $700 isn't an option on heads. If I am going to spend that kind of cash, I will go with a 5.3L and a T56. I am debating just fixing the 3.8L and selling the car. I know with minor bolt ons the 5.0L will put down good numbers and I have seen procharger kits for pretty cheap.

  13. #13
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    Well GT40s are going to run you $200, and then figure you'll spend another $250 at the machine shop getting them cleaned up and resurfaced, so you're only $150 away from a good used set of aluminum heads. If you can't scrape together the extra money for good aluminum heads, you'd be better off leaving the stock E7s on there and saving money until you can afford better ones. Between the cost of the GT40 heads, and new head gaskets and head bolts, it would basically be $500 down the drain for very little performance gain. A well built 5.0 in one of these cars can make good power and be a lot of fun, and if you spend money wisely and in the right places, it can be just as fast as the SC motor for the same or less money, but on the other hand a mostly stock 5.0 in one of these cars will be underpowered enough to ruin the driving experience, and if you are going to swap in a mostly stock 5.0, your time and money would be better spent just buying a good used SC motor, that way you don't have to worry about tracking down a parts car or rewiring anything.

  14. #14
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    My sc gets a lot better fuel mileage than my five oh. And I just did a lot of stuff to make it better.

    Like said before electric fan is a must.
    ~Chris
    SCCoA Member #1826
    Bettie Riding jack stands
    SCARlet on drag duty now

  15. #15
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    Quote Originally Posted by DeanWinchester View Post
    $600 or $700 isn't an option on heads. If I am going to spend that kind of cash, I will go with a 5.3L and a T56. I am debating just fixing the 3.8L and selling the car. I know with minor bolt ons the 5.0L will put down good numbers and I have seen procharger kits for pretty cheap.
    I think you are wasting your time if you don't want to spend money to improve the 5.0. All the effort you will be putting into a swap would be better spent fixing and selling the car. Then get a car that is more to your liking. The 3.8 is no less reliable than a 5.0. In fact in many ways the 3.8 is a better motor but that's a discussion for another time.

    No, the SC EEC will not run the 5.0. You need to do what everyone has said above - buy a 5.0 Tbird donor car and swap everything over. All that effort and an unwillingness to spend money on the 5.0 means you'll basically be ruining an SC for no purpose because the car is not likely to run again unless you put a carburetor on it. As much as the car pisses you off, you are going to be better off fixing and selling or just selling it as is and take your loss.

    I don't think you have a realistic understanding of what is involved in a motor swap.
    Quote Originally Posted by Miller View Post
    Ya thats why i tape mine down. People think its bc i dont have a moonroof seal (which is true) but its really to keep my roof from ripping off .
    Email me here.

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