Although the Mustang II is not the best layout for competition, it is a tried and true geometry for thousands of street rods and hundreds of thousands of highway miles. Many manufacturers have all of the parts needed (spindles, brakes, springs, sway bars, etc.) Of course, we hope you will use some Welder Series parts in your design.

The upper arm pivot points are shown as 29-1/2” apart. The stock upper arms adjust in slots, so this dimension is not absolute. It is a starting point, and one that can be used when the upper arms will use threaded adjusters to dial in the alignment.

The side view shows the upper arm pivot center line at the front, the center, and at the back. These dimensions will give the stock Mustang II anti-dive angle of 4 degrees.

1974-78 Mustang II stock upper control arms measure 8″ from the cross-shaft center-line to the center of the ball joint. Note that this is the center of the cross-shaft bolt hole, not the center of the dog-leg in the cross-shaft.
Stock lower arms measure 13-1/4″ from the pivot bolt center-line to the center of the ball joint.

Several builders have made their own I.F.S. using Welder Series’ Mustang II crossmember parts
(143731, 143751 & 14307) and 21902 or VersaTabs (20493) for their upper arm and coil-over mounts. Upper and lower arms can be made using 108211 ball joint housings and Welder Series urethane bushings and adjusters.


  1. craig clark says:

    Any chance you guys have an upper control arm mount for a mustang ii that instead of slots uses the gm style shims? I have installed dozens of mustang ii’s and have always despised the slot style adjusters. I have had several move, pop, go out of adjustment and one actually broke out the slot area. I have seen the gm style adjusters done and had a set designed but lost the cad files. Id be all over your kit if you had it.

    • DW Horton says:

      Sorry, Craig, we don’t have a GM shim-style upper arm mount for the Mustang II arms. We appreciate suggestions like this.

      Thanks for looking at Welder Series parts.

      Paul Horton

  2. Mark says:

    Can you give me an idea of what I will need (kit wise/cost wise) to install ifs front suspensions and four link coil over rear suspension for my 28 model A. How detailed are the instructions that come with them? This is all very new to me.

  3. Jim says:

    I have an 83 caprice 8.8 with factory four link triangular suspension that I am trying to install in a 58 apache truck. Do you have kits for that? The 8.8 has factory four link attachments and would like to utilize them.

  4. Gabe says:

    Can you give me an idea of what I will need to install ifs front suspensions and four link rear suspension for a 1955 International Metro Stepvan

    • paul says:

      Gabe, basic research didn’t give me much to go on…

      What track width do you want? This might depend on the wheel/tire planned.

      What is the frame rail outside dimension at spindle location?

      Will the bottom of the frame, at the spindle location, be higher, lower, or the same height as the spindle? By how much?

      What are the frame rail cross section dimensions? e.g. 2×3, 2×4, etc.

      This info will get us started on an answer.

    • DW says:

      Sorry Chris, we only do Mustang II crossmembers… I think Detroit Speed has some really nice options for your truck.

      DW Horton

  5. wayne priest says:

    If i buy one of your crossmembers for my 67 nova could you guys notch out on the crossmember where the frame rails go,at extra cost of course.I would buy all of the materials to make contyol arms,nice stuff by the way

    • DW says:

      Hi Wayne
      Please email Paul ([email protected]) to discuss this project.

      Thanks for reaching out.
      DW Horton

  6. Bill Philip says:

    When setting anti-dive should the frame be set at the rake that it’s going to be on the street or with the frame flat and level?

    • DW says:

      Hi Bill, thanks for asking. It’s ideal to build the whole car at ride height, including setting up the suspension geometry.

      DW Horton

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