Possible IRS idea
- Thread starter aerosteve
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I have a Corvette C4 rear IRS in my 84 Regal T-type. Absolutely Love it. Plus I run 17x11 rims with 335 30 17 tires.
The Thunderbird/Cougar/Mark VIII rear ends are really wide. I parted out a Mark VIII a few years ago and hung on to the rear suspension assy for a while but sold it because I couldn't think of a good use for it. They have an odd small (5x4.25") bolt pattern too. I think the Mustang IRS is slightly narrower and at least has the more common (Ford) 5x4.5" pattern.
Personally, I'd go with a C3, C4 or Jag IRS as a better match for a Gbody.
Personally, I'd go with a C3, C4 or Jag IRS as a better match for a Gbody.
DRIVEN said:
a C3 would be a ton of work because it is not a sub-assembly. C4 or newer, Jag, Heidts(if you had the money) would be much easier engineering and fabricating
I don't know if I'd call it a TON of work. Really, it's just a couple mounts for the front of the trailing arms and each end of the crossmember (rear diff cover). Seems to me like the Jag would be the most self contained. Not speaking from personal experience, just looks that way. They're cheap too.
DRIVEN said:
Lot more then that to a C3 fab work. It is all separate pieces that have to have the geometry setup perfect or big issues. You have to mount the diff top and rear solid to the frame, get the trailing arms at the correct location and angle. shock mounts, etc. C3 are a trailing arm IRS which at it's time were a leap forward, but because same issues that affect trailing arms on a solid axle also have similar effect on the IRS. Problem with that is as the trailing arm flex each side of the rear end can do it's own thing. Bottom line Performance and handling of a C3 or older IRS is less than a well built and set up live axle.
C4 and newer are 5 link rear end assemblies which are what you describe , basically eight main bolts, remove driveshaft, and brake line/cables and the entire rear end comes out of the Vette as 1 fully functional piece. The fabrication is straight forward( still time consuming) simply mount the differential carrier frame(batwing) and the 4 link bars, then either frame mount the front diff point or build a torque bar to transmission and you have an IRS.
Jag is a very similar setup and yes Jag would also be an easy fabrication. Thing I disliked about the jag setup is the inboard brakes. Look cool , work awesome, but lot of work to do a brake job.
Heidts IRS is based on a jag setup, just with many improvements and shiny pieces.
Hmm. I've got an '81 rear sitting in the corner of my shop. I guess I was remembering it as an easier install than it is. Guess I need to drag it out and take another look. Thanks for the info.
DRIVEN said:
81 may have the batwing mount for the center and be an aluminum dana center carrier, but still trailing arms. I know somewhere around 80-82 they changed that part of C3 from the earlier steel center sections also you may have the fiberglass mono leaf instead of the earlier multi leaf steel one.
I spent a lot of time researching options for putting IRS in my Regal. It is not a weekend task no matter what you go with.
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