4.0l to 4.6l swap questions

Discussion in '2005+ Ford Mustang v6 4.0L Tech' started by Derby, Jan 2, 2022.

  1. Derby

    Derby Junior Member

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    Hello, new to the site. I looked around but could not find the answer. I hope you can help.
    I purchased an 07' mustang 4.0 manual shift for my son. The guy I bought it from had a complete 07' GT 4.6 auto set-up. My question is, will the GT auto pcm mate with the car? I have the column, instrument cluster from the gt but I do not have the pedal assembly. Would it be easier to stick with the manual?
    This swap won't happen until next fall. We are going to go through the engine this winter and spruce it up before the install.
    Any advice is appreciated.
     
  2. Joe combs

    Joe combs Member

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    The swap itself is pretty much basic... BUT... the 05 wiring is not a direct plug and play with the 07 engine harness setup. You will need to get wiring diagrams for both years to be able to make them work. The BCM in the passenger kick panel will be setup for a manual trans and will create an issue of not allowing the automatic shifter to come out of park. Is the V6 an ABS brake car?
    The manual from the V6 will not bolt up to the V8 engine...
    There is plenty more stuff that you will be needing to make this swap work... exhaust hangers, correct ratio V8 rearend (3.31 or tuner) driveshaft.. the brake pedal... the high pressure power steering hose is different ... the brake master cylinder reservoir. You are gonna need access to either a salvage yard where you can get there extra parts, or a donor to get parts from.
     
    john knox likes this.
  3. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor Official Vendor

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    This is an oft asked question: How do I swap my V6 (enter car here) to a V8 of the same model, which the factory also offered?

    Answer: You don't

    Honestly, the only "swap" here that isn't a HUGE waste of time is to: take any parts off of your V6 Mustang that you like and sell it. Then buy the V8 version of the same car, swap on the usable parts from the former V6 car, and save yourself HUNDREDS of hours of frustration and pain, and potentially thousands of dollars in parts / work.

    [​IMG]
    This 2010 Mustang GT 4.6L we swapped to Gen II Coyote 5.0L was a LARGE pain in the ass...

    Seriously, this is not a smart swap to do... The 4.6 3V isn't even that good of an upgrade (300-315 hp vs 420-460 for Gen I-III Coyote 5.0L), and when the factory made the exact setup you want this is just a bad idea. Sell what you have / buy what you want and you are miles ahead.

    [​IMG]

    And this is coming from a shop owner who has V8 swapped 13 different car makes/models and has delivered 500+ V8 swaps for the past 20 years. I doubt if anyone else on the planet has done more modern V8 swaps / kits than us. So maybe I know what I am talking about here: you are just wasting time.

    [​IMG] [​IMG]

    Unless you are building some hybrid engine swap that never came from the factory we always REFUSE to do the swap work like this - because you can just go out and buy one of hundreds of thousands of S197 4.6 3V cars used and it will be a BETTER swap than you could junkyard / home brew.

    Cheers!
     
    Last edited: Jan 5, 2022
    WJBertrand and Dino Dino Bambino like this.
  4. Derby

    Derby Junior Member

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    Thank you for the reply.
    The car and the donor parts are both 07'. I have the GT complete drive train from crank pulley to differential. Both are ABS. I have the complete front subframe with power steering and master cylinder still connected. I have both pcm's. I have the complete GT dash w harness. I do not think I have the bcm unless it is bolted to the dash frame.
    So that is the first issue I will run into. The brake pedal is another.
    I assume the PATS system works through the bcm?
     
  5. Derby

    Derby Junior Member

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    Vorshlag-fair, thank you for pointing out the pitfalls of a swap like this.
    My son is going to drive this as a v6 through next summer. We were planning the swap for next winter. Who knows maybe I will find a GT with a blown engine cheap and this swap won't happen.
    In the mean time I want to be prepared if we do the swap.
     
  6. Joe combs

    Joe combs Member

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    Derby...being both are 07 it should be direct plug in, with only the engine/trans wiring being unplugged and removed then. None of the rest of the cars wiring should need to be touched. The V6 car BCM could be reflashed to the V8 configuration to make it work as needed.
    If you need any help shoot me a message, I'll help you as much as i can.
     
    Derby likes this.
  7. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
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    You're settling yourself up for a hell of a lot of unnecessary work. Do you have the whole donor '07 GT as a running vehicle or is it just a parts car?
    Firstly I suggest you buy a decent '05-'09 GT with a manual tranny and sell your '07 V6. If your '07 GT parts donor is a complete running car, sell that as well. Otherwise you could sell the tranny plus any other unwanted parts, and rebuild the engine with upgraded components plus LT headers ready to swap into the newly purchased GT.
    Alternatively, sell both the '07 V6 plus the '07 GT and use the funds to trade up to an '11-'14 GT. Then you can have 412-420hp right off the bat with your choice of tranny.
     
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  8. TexasBlownV8

    TexasBlownV8 Formerly TexasBlownV6

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    If you have a complete GT drivetrain from a donor car (and can't get the GT on the road for some reason or another), the swap IS PRETTY EASY. I have a writeup in this forum, and have done numerous v6 to v8 swaps myself. When the donor and recipient are the same year (i.e. 2007 in your case), it is much easier, too.
    Essentially you'd put in the engine, trans, rear end, driveshaft, exhaust, and PCM from the GT into the V6. You can also put in the GT instrument cluster as an easy upgrade.

    Easrly last year, I purchased a '07 4.0 that had the engine destroyed, but the rest of the car (and driveline) was intact. I had already come across a great donor '07 GT drivetrain from a salvage car, which was unrepairable, but the drivetrain was supurb. That v6-looking car is now one of my 'daily drivers'.
    If you can do the work with helpers and friends and can keep labor costs down, it is a VERY DOABLE AND LOW COST swap. Don't listen to those who say 'it can't be done' or 'not worth it'!
    Feel free to PM me if you can't find my writeup or need more information. Good luck!
     
    Derby likes this.
  9. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor Official Vendor

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    This is a needlessly high effort swap and big bag of hassle for a lackluster end goal ('07 GT) that you can just go out and buy for $5-9K running, never breaking a sweat.

    It is only "worth it" if you value your time and effort at ZERO. Some people have a very low value for their time... I try to remind people that their time DOES have value. Do you go to work every day for FREE? No? Then your time has value...

    [​IMG] [​IMG]

    Again, we do engine swaps for a living and I try to encourage this, but only when it isn't completely pointless and without some special end goal. This swap idea is just about being cheap, and only achieves something that anyone could buy in an afternoon of looking on Autotrader or Craigslist.
     
  10. DieHarder

    DieHarder Senior Member

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    Understand the "business" aspect of it. However, if the goal is "father/son" time and creating memories/ learning together there are few ways better than building a car. In this case they have the correct years models/harnesses to swap over so it should be little more than plug & play after an engine refresh and swap over of appropriate V8 items/parts into the V6. I would however swap over everything usable from the V8 into the V6 wiring-wise to prevent any compatibility issues. The auto to manual issues ask others on the forum as I have an auto and doing just fine. You could of course elect to make it an auto also which would make it truly plug & play. Auto PCM & all. You can likely get an auto pedal assy at a junk yard.
     
    Derby likes this.
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