Club Cobra - Jag Suspension

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I am still researching manufactuers. However, I am fairly certain I am ultimately going to buy an E.R.A. 427. I am committed enough at this point to start acquiring parts listed in your builders manual. I note that Jag XKE and pre 1984 XJ's are recommended for rear suspension. What about early XJS. A guy out here on the coast sells fully operational units for what appears to be reasonable prices--but the XJS units run $250.00 more than the XJ's. Is this because they all have limited slip? Also, when you say many XJ differentials were "open" (page 15 of manual), does this mean it does not have limited slip or positraction? Finally, did some XJ6's come with limited slip?
Thanks,
malibu

I can shed a LITTLE bit of light on this. "Open" means for sure it is NOT a posi traction type unit. Open is often referred to as a "one legger", "a peg leg" etc., one tire spins not both.

I've had several XJS's (hey, I LIKE them). ALL the ones I had were "posi" units, maybe I got "lucky"? The XJS rear end is stronger than the XJ's had. But is probably not "lighter" over all. I was able to "break" the posi unit in several rear ends in the XJS, as I drove them HARD! I would be skeptical an XJ rear end could hold up to the high horse power normally found in a Cobra when used aggressively.

Then again, the XJS's were a HEAVY car. The cobra being lighter may well be fine with the standard XJ rear end. But NO WAY I would EVER use a "peg leg" in my car!

So why don't they recommend the XJS rear end as opposed to the XJ rear end? Price might be one reason! A lot of kit makers try to use examples of "donor" parts that are easy to get or are at a good price or have that sound of "good stuff" associated with it. That doesn't mean it's the "best way"!

Ernie

PS
Just broke the posi unit in my 9" Ford rear end too. I'm just HELL on wheels when it comes to breaking stuff, doesn't mean the Ford 9" is "weak", heck it's considered about as strong as they get!

Hey Malibu John, I have series 3 XJ Jag rear in my car with a limited slip, pretty sure it is around 3.5 ratio. We are pulling the centre out and installing a 9inch conversion into the centre but still retaining the independant rear assembly.

We've had good luck with the Jag limited slips, but we have all of them rebuilt by Reider Racing.

Any Jag rear with inboard brakes will fit.