Sticky: I6 to V8 conversion

Discussion in 'Classic Mustang Specific Tech' started by Rusty67, Jun 12, 2007.

  1. I think you missed the boat.

    The point of this isn't for people to go buy an I6 and convert it to a v8. It is for people that like their I6 but want a v8 in it.
  2. revisiting this thread.... as far as your cost analysis goes. If I told you the amount I have into this car I would be embarrased and I don't even have the motor in it yet, I could buy 3 v8 cars at this point. for those thinking about it.... my suggestion would be..... think long and hard before endeavoring down this road with me.
  3. If all you want is a stock v8, stock worn out suspension, etc, etc, etc, it is probably cheaper to buy a v8 car. I looked a several v8 cars and realized that ALL the drivetrain, suspension and brakes would be modified so I saw no need to search for only v8 cars. I found i6 cars in general were sometimes half the price for a car that lived a relatively easy life.
  4. I was in on this thread long ago, I wouldn`t dare tell a soul how much money is in my car now, especially my wife...
    MustangDiva likes this.
  5. we should go have a beer LOL
  6. Yea I think we both would have some interesting stories. Saving money doing it myself...yea right.
  7. LMAO! Mine now runs! And is quite the beast.

    And yes I was keeping a nice spreadsheet with parts and totals. At a certain point I abandoned that idea as it made me a bit ILL lol!

    Anyone thinking of doing this. Turn around and run, run very fast. Although it can be quite gratifying, it will be hell all the way to the end. many a time laying underneath this car I thought to myself, I should just sell this friggin thing!!!

    But then I hear this and smile
    mustangmutt and MustangDiva like this.
  8. Makes all that hard work worthwhile doesn't it? I do not think the Gods are frowning at you either. That sounds tough!
  9. Took the Stang up to a cruise night for the first time tonight with it's heart transplant complete. this car if friggin wild. just shy of 400 horse on the dyno the other day.
  10. Well its finally done.

    it was a long expensive road. an I6 to v8 conversion is not for everyone. There were soooo many times I wanted to just throw a match in it. But in the end it worked out great. I am driving the car now, and enjoying it with my daughter, which is what the whole project is about. Oh and it dyno'd out at 375 horsepower at the rear wheels, which makes it fun for me.

    How it began life:

    After the transformation:


    Yes, Body and paint are next, but its going to be a little bit. she looks good now, but she's not perfect. But being an Arizona car, she is in great shape.
  11. I'm only going to comment on this because I'm tacking this job right now. No my car is not a show winner, no I'm not using all new parts at the beginning but I am swapping my car over.

    To start- My car is a 68 Mustang I6 3 Speed Manual.
    Needs patch work on the floors, and a door skin but other than that she's in great -solid shape. I bought it for $1500 and it still runs and drives.

    So far- I bought a complete 1970 302 V8 C4 and 8" drivetrain for $450 that is running/driving (the car rusted beyond repair for the owner). I bought complete 5 lug spindles with fairly new brakes on them for $100. I now need to buy the frame bracket/engine mounts for the V8 ($100), run some tranny cooler lines, along with other minor details. But for just over $2000 I'm going to have a nice running V8 coupe. Over the winter I'll be replacing other parts (suspension, interior, new paint) but I couldn't find a rough condition V8 car locally for under $5,000. I've now seen 3 I6 cars for under $2000. I don't really consider this all that complicated and/or hard if you are just swapping it over without rebuilding everything. Maybe its just on my car that is easier than previous years, but I don't know for sure.

    my .002
  12. The '68's are definitely easier than the '65-'66 cars. And if the V8 engine & drivetrain you got are all in good shape, then you got a great deal. Unfortunately, it's hit or miss when buying used parts, especially if it's something the seller already pulled and can't start up.

    My '66 is a rust-free California/Nevada car that made it's way to Central Florida in the early '90s. It was a driver-quality survivor as it's had a newER paint job(late '80's? new), a refurbished interior(I think), and a rebuilt and detailed drivetrain; it's never been fully restored. I might've been better off selling it and finding a V8 car. I've got a carb'd Mountaineer 5.0 which is being dressed as a period correct 289, rebuilt c4, and rebuilt 8" truetrac rear. The plan is to respray it after the swap, and have a mild restomod which I can continue to modify.

    Unless you can find a V8 parts car(not so easy these days), or are stripping down to the body to replace everything with new components anways, the swap would really make very little sense. For what I'm doing, starting with a V8 car in the first place would've been a good call (if the body/interior is as nice as the I6 car you have), instead of studying every diagram in the Mustang Restoration Guide and having to buy every little part. But this was my first car(I joined Stangnet after getting the car when I was 15), and I plan on keeping it forever.
  13. Glad I'm not the only one doing things "backwards." LOL

    Are you planning on staying with the same color?
  14. Don't worry we aren't backwards. Growing up this is how everyone did it, this way you don't screw up the paint while doing all the mechanicals. I'm either going Red again or I may go blue with dark silver stripes.
  15. Okay I've been thinking about this operation for quite some time now and I believe it is worth the money and time. My 66 was a gift from my father on my 17th bday and it already has 5 lug conver. All around with single piston disk brakes in the front. But I'm not sure if my rear end is an 8 or 9". Is the rear end either one because of the 5 lug conver? My dad says he put a bigger radiator and my boss at America's tire says its good for a v8. What else more do I need besides motor and tranny, motor mounts gas linkages? I'm trying to figure out how much money I will need. I don't need a beefed up motor but I do want more than what this i6 is giving me. Any advice is gladly appreciated.
  16. Hey Danie, there are several websites that go into great detail on what you want to do. Give them a search, hit up 4 or 5 of them, and look for all the things they have in common. That's a good start. Then look for little details that might apply to your specific application.

    Can I offer you up some things to think about first, though? And this is coming from an "old guy" with a '65 who's done about everything imaginable . . . wrong. :) . . . since 1986.

    This is probably NOT what you want to hear, BUT . . . ever think about putting a really good and modern V6 in it, instead? Before you scream blasphemy, let me explain! LOL!

    You say you don't need a "beefed up" motor, and that's a very mature observation. When you're talking about a relatively normal what I would call a "vintage" V8 (289, 302, 351x), TO ME, you're talking in the 200 to 300 hp range realistically. That's WELL within the range of good, modern V6, too. You may at least want to consider looking in that direction because, if we are honest with ourselves, performance is probably a non-issue for a daily driver between an older carbed 302 and a modern V6.

    Think about it in the long term, really. Yeah, an older V8 CAN have good longevity, but typically they don't compare as well to a modern motor . . . especially when YOU can pick the motor. If you're going to be driving the car, I mean REALLY driving the car, it matters.

    And where it REALLY matters is gas mileage. Think about it. You've got a 300HP V6 in a 4,000 pound vehicle getting 30ish MPG. You take that same powertrain and put it in a 2,800 to 3,000 pound car, take off some of the power leechers, and what's your mileage going to look like? How likely are you to drive that version of your Mustang instead of you 17 MPG V8?

    If you keep the car, you're going to start running into real space problems "up front". Our poor girls don't have a lot of room under the hood for the things that make life easier. I mean, sure, you can stuff a 409 stroker motor in there (heck, I did! :D), but fitting in power brakes, a GOOD radiator, and all the other things we eventually want eats up lots of room fast. Putting in a modern V6 with lots of room solves lots of problems long term.

    Honestly, I'm not too sure about what's available now for an application like I'm describing. I'm a few years away from a complete "redo" on my horse, but I'm eyeballing the turbo sixes that they're putting in the new models. My wife (whom I met on Stangnet, oddly enough), wants another stroker motor, but honestly, getting 14mpg really limits weekend trips that we used to enjoy. Change over to 400HP, 100k first maintenance, and 25 to 30 mpg, and my little short range hot rod becomes the first car out of the garage.

    These are just some thoughts, and don't take it like I'm telling you what to do. To me, I'm a driver and not a mechanic per se, and my fun isn't tinkering as much as it is drving the car. Also, I DRIVE mine, every chance I get, so being able to hit the keys every time is more important than "trick" or "cool". It sort of sounds like you're looking at the same thing. :)
  17. It's not my daily. My motorcycle is my daily. It is my vehicle that I take out once in awhile like once every 2 or 3 weeks. I also fell in love with the way the look and sound of the v8. Don't get me wrong your suggestion is a good one with a daily only in my perspective don't mean to seem rude at all. She's not my daily I don't want to be putting miles on her. Love the per and look of the v8. You don't have an idea on what else I am going to need? I want to put a 302 with a t5 5spd, carbed as well love the look of it. And I'm not good with computers and electrical so that's why carbed.
  18. Here's pretty much the "kit" and instructions for doing it.

    For what it's worth, there are a buh-jillion websites showing all the steps. :) You're in good shape there as this is a relatively common swap albeit a real pita.

    One of the issues common is finding a 9" that will fit. Our horses have a fairly small spread in the back, and "normal" niners don't fit. The Versey 9" fits great and even comes with rear discs. On the down side, good luck finding one. Around here, they're pretty rare. Back in the late 80's, Stang people were snatching them up left and right along with the old FMX trannies. Go figure. Again, though, there are a buh-jullion different websites showing rear end options for 1st gen Mustangs.

    I'll offer you this one as a for what it's worth. As long as you don't mind drums in the back, the 8" rear ain't so bad. I had an 8" behind my first 351W, and HONESTLY, I cracked the casing and not the mechanicals, and that was after a few years of relatively sane driving. If you're really building a mild 302, an eight will probably hold up just fine.

    A heads up on five and six speeds, too. From what I recall, there are a bunch of those transmissions that have integral shifters i.e. the shifter is actually part of the transmission. Again, just going from memory, they don't fit the normal shift hole for a 1st Gen. They end up being too far forward. There is actually a conversion shifter for them, but to me, it looks hokey, and it's got some exposed linkage. I'm an old guy so I have a Toploader. At the time, I didn't have a lot of options (1988). Neither the rear nor tranny has been touched since 1988, and I'm close to 200k, most likely. If I had it to do over today, meh, I'd do an 8.8 and a T5-6 or something. Since mine TRIES to be a daily and I do like long road trips, I'd make it back up in gas money (or that's what I tell myself, at least).

    The 302/T-whatever with a carb is really pretty mundane . . . which is EXACTLY what you want because lots of people have done it, still do it, and they're free with their advice. Honestly, the EFI route is mundane as all get out NOW, so I wouldn't rule it out. Going with IBM instead of Holley is the . . . THE way to go for a driver.

    One thing I will warn you about now is that, sadly, our old girls ain't running with the new stuff without SERIOUS help. I love my big stroker, and it's still in the 500HP range, BUT compared to even some of the mid-level four doors, I'm hurting. We bought a 2006 Charger R/T, and it's been downhill from there. I mean, yeah, the rumble and grumble is fun, and yeah, I've got gobs of power, BUT so does the new stuff . . . with power everything, 24MPG, and first scheduled maintenance to be performed by your grand kids when you let THEM drive it, eventually. I grew up when a "mildly modified" 302 was a lot of fun, and a good Windsor made people think twice. Now, though, sheeeeesh . . .

    Good luck in your endeavor, though! You're not doing anything "new", so at least you have a good road to follow.
  19. My sugestion is to either junkyard a setup or buy a donor car/wrecked runner.
  20. This is A GREAT IDEA . . . assuming you can find a really cheap donor car like a '65 or '66 V8 car that's not damaged anywhere significant so you can cut it apart to turn your I6 car into a . . . '65 or '66 car with a V8. :D

    Probably 30 years ago you could get a donor car cheap, but the problem now is that these cars are in demand sufficient enough to make fixing them up profitable, especially so if it's already a V8 car. Also, since you can get about anything for a Gen 1 Mustang, it makes them even moreso. Naturally, you have to ask yourself why you would cut up TWO cars, one perfectly good I6 car and one probably salvageable V8 car, to make a hybird car that is REALLY neither, anymore? TO ME, if I had a good I6 car, and I found a mildly damaged V8 car . . . heheheh . . . I'd drive the I6 car to work, the parts stores, and shows while I fixed up my V8 car. :D

    The junkyard idea, though, you probably have some good ideas there, though! :)