The "Mustang II" IFS Real Info & Debate Thread

Discussion in 'Classic Mustang Specific Tech' started by reenmachine, Sep 17, 2007.


  1. Mustangmaker67

    Mustangmaker67 New Member

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    Well, I've tried to to stay silent in all this. Reading all these post is giving me a headache. I'm not sure how many of these MII are out there, but I for one, have installed several. I'm also planning on installing more. I have had 0 failures. I've had 0 Complaints. I've had 0 problems of any kind. I have cut out several cracked, broken, twisted, rusted, totally failed Shock towers. What will the MII do after 40 yrs? Probable the same, Would I road race my 67 Fastback with MII? NO WAY. Would I road race your 67 Fastback with a MII? I would drive it like I stole it. Now Then, If anyone is fool enough to chance their car in that way, the suspension under the front won't make much difference. Let's face it, most of these cars are beautiful restored classics. The majority of owners drive them with some care. The owners that don't, should care about twist, fatigue, failures, It's going to happen. I agree with Reen, If your restoring a Mustang, and your going to take care of it when your done, a MII is a great option to get all the neat things you want in one package,(Disc brake,Rack,Ect). It is very simple to install. However, If you can't weld, It's a problem. But really, if you can't weld, a restore on most Mustangs is a problem. If you like a 40 yr old suspension that is tried & true, then the original setup is best for you. Of course, I wouldn't change to Disc front brakes either, Those old Drums are tried & true too!!! Just my 2 cents worth, I don't really have any degree, I've just been restoring these old Rust buckets for 21 years now. WWW.Mustangmaker.com Thanks.
  2. dmoody

    dmoody Founding Member

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    I have cut/repaired several shock towers from the early cars as well. You failed to mention the reason why the majority of the shock towers are ruined in the early Mustangs... its because owners had to cut holes to grease the suspension. This was often done with a blow torch that warped the shock tower and blew holes big enough to stick the entire grease gun through. Time had nothing to do with the shock towers failing on the Mustangs I've restored.

    As for the MII, it doesn't have shock towers so they definitely won't fail in 40 years. You are comparing apples to oranges. Even though the quality of the cars was pretty shabby in the 70's Ford did learn a few things.... like how to use grease fittings and galvanize inner cowls. Don't get me wrong, I LOVE the early Mustangs and have owned nine different ones. However all Mustangs weren't built with the same flaws. In 40 years what you'll repair on a MII won't be the same things you'll repair on a classic Mustang. If you ever restore an MII, you'll spend most of your time puzzling over the plastic auxiliary gas tank and warped urethane bumpers but the suspension you'll probably never touch.

    David
  3. mikethebike

    mikethebike Member

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    Ditto. My wifes 1975 V-8 MACH-I drove so much better than either my 65, 66, 67 or 70 cars. I did the stage II to the BOSS-302 and I would still rather drive the 75 on the Blue-Ridge Parkway. I had BFG T/A's, Mulholland shocks and front springs stiffened by about 20%.
    It was a very nice car to drive.
  4. 69gmachine

    69gmachine Member

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    Why would you remain silent? This was an open invitation to a constructive discussion.

    :rlaugh:
    I just want to point out that there is a considerable difference between an Open Track event and a real race. However, I'm an adrenalin junkie and the day my car comes out of the paint booth the next time, I won't hesitate to head for a track. A public road with aggressive, drunk and preoccupied drivers everywhere is far more dangerous IMO than a controlled event with prepared cars and drivers.

    Twist and fatigue are definitely concerns with 40 year old sheet metal. The car should be structurally sound before getting on a track. The owner should inspect the car thoroughly and replace/repair as necessary. If you go beyond the beginner group, you need to upgrade your car with the appropriate safety equipment. No matter how prepared your car is however, it is inherently dangerous.

    Not everything requires a degree. There is no substitute for experience.
  5. mustangracer

    mustangracer Founding Member

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    One of the major initial issues with the MII kits was not the suspension to frame interface, but the rear mount of the lower control arm. The first kits I ever saw didn't have the triangular gusset in the above picture, and several suffered failures of the rear control arm mounting. I recall one was a 55-56 Ford truck with fatigue failures around the lower arm mounts.

    Given the weight of the truck, I would compare it to moderate track use for a lighter car like a 65-66 Mustang, therefore even with the gusset I wouldn't consider using it on a car that would see even autocross use. The "engineering" in the MII kits was probably never intended for much more than street duty (if there ever was any engineering done).

    Since I didn't bother to read the entire thread I'll refrain from the discussion of installation issues.
  6. valvmustang

    valvmustang New Member

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    Thanks to all for a very interesting tread :)
    What I can read out of this is that there is pros and cons with the original and the MII suspensions on the classic Mustang, but none of them are superior - what is the best front suspension I can put on my old Mustang then?
    I as a lot of others have to get rid of the shock towers due to problems with space, and therefore I have to get rid of the shock towers....
    I have been looking at some of the manufacturers of MII suspensions and my choice right now would be Heidt's. But are some of the others better, and if so, why?
    The insatallation of these kits looks straight-forward (I'm a qualified welder) but are there any traps I should look out for when installing any of these kits?

    TIA
    Stig
  7. bnickel

    bnickel Founding Member

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    i prefer the Martz chassis kit to any of the other Mustang II style suspensions, if you must cut the towers then you absolutely need to have the brace from the front of the frame rails back to the firewall and the Martz kit includes those already. may ask what it is you're working and why you need to do away with the towers? you might be surprised there are other ways to get more room without totally removing the towers, depending on what it is you're doing.

    here is the Martz kit.

    http://www.martzchassis.net/page3.htm

    it also solves some of the problems others have mentioned about the lower control arms too, since it still uses the strut rods. and you can pre-formed aluminum fender aprons and radiator support as well, plus the stronger frame rails and the aforementioned frame to firewall braces all for around the same price as the heidts kit, well the fender aprons and rad. support are extra but they save you the time and hassle of having to fab them yourself.


    my thoughts are if you're going to go that far whacking out the shock towers might as well go all out and do the whole front clip, heck if you're careful removing it you might even be able to salvage the clip and either sell it or save it for some future time when you might want to restore the car back to stock. just a suggestion.
  8. valvmustang

    valvmustang New Member

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    I've moved my engine about 3 inches backwards (due to weight distrubution and shifter location), and with the headers supplied with my twin-turbo kit the turbos will end up in the middle of the towers.....

    Yeah I've looked at the Martz kit too and like their concept, but it looks rather big and heavy so I doesn't dare to think what the shipping will be all the way to Norway.
    I can still make some frame to firewall braces without removing the fender aprons, something I planned to do anyway as a extention of my rollcage ;)

    Thanks for your input, I might check out the shipping and decide when I know that :)
  9. bnickel

    bnickel Founding Member

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    i didn't notice you were in norway. yeah shipping would probably be a killer, but you never know.
  10. reenmachine

    reenmachine Active Member

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    So here's how I did the front frame reinforcement. The bumper brackets fit through the square section in the front, which is a bit oversized in order to fit my rotisserie. I plan on gusseting that part up a bit for stiffness once the rotisserie work is done. The upper firewall area is reinforced with 1/8" steel.

    [​IMG]

    [​IMG]
  11. bnickel

    bnickel Founding Member

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    i guess that works as well, i'd still rather see them connect directly to the frame rail but with gussetting it should be fine.
  12. mustbereel

    mustbereel Member

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    My approach to the same issue. Like Reen I wanted the braces under the fenders mostly due to the 4.6 DOHC going in there. It also keeps the engine bay uncluttered. I also like the idea of attaching the brace to the area where the cowl, cowl side and firewall meet. This is a very strong point in the unibody.

    The brace is contructed from 1-5/8" 10ga. structural tubing. The sheet metal is 12ga. The brace is anchored at the top with a 12 ga. bracket and at the bottom with an 1/8" angle. The purpose of the sheet metal structure is to provide a mounting point for an export brace style diagonal. The diagonal connects to the cowl where I have added a 12ga. angle for reinforcement.

    I assembled the front suspension and mounted a 245/45/17 tire on a 17x8 rim with 4.75" backspacing. I left out the spring so I could move the tire through it's full range of motion, up and down as well as lock to lock. The brace was designed around this so that there would be no interference.

    Once I get back to my torsional testing I'll post the results in my thread.

    [​IMG]

    [​IMG]
  13. 1970 slantroof

    1970 slantroof Founding Member

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    I made a similar but yet different brace for the front of my 1970 sportsroof but I don't know how to post pictures. (computer ingrate). My reinforcement is on the inside rather than outside. If someone will post the pictures for me I will send them to you.
    Thanks,
    Howard:hail2:
  14. Mustangmaker67

    Mustangmaker67 New Member

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    Reen, have you mocked up your tire/Wheel on that set up? If so, did you have any clearance problems? Looks kinda tight up front. Also we've been having our inner panels cut locally with an extra square tab on top & bent down in order to remove all of the original shock tower. It also enables us to resale the original shock towers if they're still useable.
  15. reenmachine

    reenmachine Active Member

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    I did indeed mock it all up just for that reason, and there are a couple of inches to spare.

    I don't quite follow what you mean about the inner panels. Have a pic?
  16. reenmachine

    reenmachine Active Member

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    If you email them to me I'll put them up here.
  17. reenmachine

    reenmachine Active Member

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    Here are the pics. Looks nice! Love that shade of yellow by the way.

    [​IMG]

    [​IMG]

    [​IMG]
  18. Mustangmaker67

    Mustangmaker67 New Member

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    I was talking about the filler panels. Normally we cut thru the upper corner just above the shock mount and weld that to the new filler panel. With this new filler panel ,with the bend, the entire shock tower panel is removed and a cleaner bent panel welded in place of it. I'll try to post some pics on my web site & here. WWW.Mustangmaker.com
  19. reenmachine

    reenmachine Active Member

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    I totally understand what you're talking about now. That'll make for a cleaner installation.
  20. bnickel

    bnickel Founding Member

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    looks like fatman just threw a new wrench in the works

    http://fatmanfab.com/catalogpage.php?page=21

    not sure it's for everyone but i'd be more apt to use this than a regular mustang II conversion, this is more on par with the Martz kit i posted earlier.

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