Factory Five Racing Forum banner


  1. favorite gear oil for the IRS setup?

    Factory Five Roadsters
    I ordered my rear IRS from Mike Forte https://cobradreams.com/2019/12/11/ordered-the-irs-center-and-knuckles-today/ and it had to be drained since it wasn't on a pallet... I know many of you have installed the IRS, and I don't want to start a holy war - but I've seen tons of info on Amsoil...
  2. Replacing CV Joint in MK3 with IRS

    Factory Five Roadsters
    Hello, I have an MKIII with an IRS that is making a clunking noise every time I accelerate or decelerate for the last year or two (driving me nuts). This year I decided to fix it so I have since replaced the old Ring and Pinion gears with a Richmond 3.55:1 Ring and Pinion gear kit (old gears...
  3. Wonderful to be building again

    New Member Introductions
    MK IV kit delivered in Spring 2013. Got a good start, but had to focus elsewhere. Moved. Now get to spend a couple days a week. Not a show car; not a race car. Just a very clean build with lots of help from the Forum.
  4. help with shock selection

    Brake and Suspension Tech
    Guys I could use your help, I am building a scratch built kit car. It is a Mercedes Gullwing replica however its design is very similar to a Factory Five Cobra. I have a Heidt Mustang II front crossover with their tube control arms, front strut eliminated, Mustang II front spindles. I am...
  5. 2015 IRS assembly For Sale

    Parts For Sale / Wanted
    2015 IRS assembly** SOLD ! I have up for sale a New Take Out 2015 Mustang IRS. I bought it with a project in mind but That project is going to be put on the back burner. This IRS is an aluminum center section that came out of a brand new 6Cyl. auto car. This IRS will work with FFR's new IRS...
  6. RustlesRoadster

    Factory Five Roadsters
    OK, so I received my M4 roadster kit about 2 weeks ago but FFR has back ordered some of the key ingredients needed to get me started. Body is on the buck and frame is on the dolly awaiting said parts. So, I'm biding my time accumulating the needed bits and pieces. Found a '98 Lincoln M8 IRS...
  7. 20 years later and just getting started

    Ford Modular Engine Roadster Builds
    FFR Base kit, 5.0 Coyote, Tremec 600, IRS 3.55 with Eaton Trutrac I bought the base kit with lot's of extras a year ago and took delivery about 10 days ago. It's funny how much things have changed since I first looked at and lusted after the MKI. I've gone from having kids, and no money or...
  8. For Sale: 2004 Mustang Cobra SVT IRS 8.8 Complete 31 spline Rear End 38k miles

    Parts For Sale / Wanted
    Sold SOLD 2004 Mustang Cobra SVT IRS 8.8 Complete 31 spline Rear End 38k miles I decided to change directions with my IRS and no longer need this. Here are the details: Donor was a 2004 Mustang Cobra SVT w/ 38k miles Purchased from Midway Mustang in Davenport, IA on 3/17/2014...
  9. IRS Pinion Angle

    Factory Five Roadsters
    Trying to get this right so I can get my drive line ordered. Forgive me if I get the terms wrong. The way I understand it is I measure the vertical angle of the rear face of the transmission and the vertical angle of the pinion on the rear end (where the drive line bolts on). I then put...
  10. Drill rear Wilwood hats?

    Factory Five Roadsters
    Per the instructions and some old forum posts, the rear Wilwood hat wheel stud holes may need to be enlarged to fit all the way onto the Ford Racing kit car hubs. Is this something that can be done on a drill press, and the round drill bit finds the center of the round hole and all is well? Or...
  11. For Sale: FFR Mk III - IRS - 5.0 Quad-cam Florida

    Factory Five Cars For Sale by Intercity Lines
    SOLD pending receipt of funds 1965 Factory Five Racing COBRA replica #1004554RD 5.0 quad-cam Ford Cobra engine, Independent Rear Suspension Perfect Street and Track driver - Florida title: "1965 FFR" $35,000 This is my third FFR Roadster build, completed in 2007. It is an IRS car, with a 5.0...
  12. Mk I to paint finally

    Factory Five Roadsters
    Finally got my MkI down to Temecula to Jeff Miller. He said he hasn't seen one in a long time, but assured me all will go well. I am going with ivy green metallic.
  13. Thinking ahead.. what is next to break

    Factory Five Roadsters
    So the old girl is getting the motor rebuilt after I blew up some pistons - planning on it being stronger than ever. I am also going to be putting some MT E/T Street Radials on the back so I can finally hook up and have some fun. This got me thinking though. I am pretty sure the TKO600 is...
  14. Question about IRS on non-donor build

    Factory Five Roadsters
    Hello all! First let me start by saying that I am right now in the planning stage of my future build, and I have many questions. I see that this forum is a great place for information. I have already tried to use the search function for the answer to this question, but I was unsuccessful. I...
  15. Seeking Photo

    Factory Five Roadsters
    Anyone able to direct me to photos of Levy's rear brakes on an IRS car? Specifically how the aluminium bracket is mounted. I got the stuff and won't be able to be at my car for a few days and would love to have some visuals to think about it. I have a Pin drive read and swapped the rear...
  16. IRS Knuckle to Control Arm Fasteners

    Factory Five Roadsters
    What size are the 6 bolts that connect the upper and lower control arms to the knuckles? It looks like the upper control arm to knuckle bolts are a different size than the lower control arm to knuckle bolts. Obviously these must be Grade 8. I normally buy parts from forum vendors; but I...
  17. Center Section assy ?

    Factory Five Roadsters
    I have a Ford Racing Aluminum 8.8 Center Section for my roadster's IRS, and I am assembling the cover/girdle. While following the instructions on applying black Permatex as the gasket, the question comes to mind - Do I use just anti-seize, or anti-seize AND lock-tite to bolt the cover on...
  18. Want to Buy: IRS Spindles

    Parts For Sale / Wanted
    Rear spindles +hubs needed, ABS not needed, to be placed under Levy 12.2" brakes w/ 4-piston calipers. Wheels are FFR Halibrands. Already have a pumpkin. Thanks!
  19. IRS parking brake help

    Factory Five Roadsters
    I am plugging along with my build, and have encountered a problem that I believe is commonplace. I am building an IRS rear with cobra brakes and cobra rotors. The parking brake cable barely fits, and it appears as if I am going to have problems with the cable rubbing against the CVs. Here are...
  20. Pin Drive IRS vs. Standard

    Brake and Suspension Tech
    Does anyone know where the difference is in width for the Pin Drive vs. Standard IRS? I am wondering if they leave the control arms at the same length and narrow the cradle or if they leave the cradle the same but have shorter control arms. I don't have a FF car (yet), but I really like the...