I'm going to switch out the live rear axle in my '01 GT for the 03-04 Cobra IRS, but I'm unfamiliar with them and don't really know what to look for to find one in 'good condition' or if that is even a thing. I'm planning on replacing all of the bushings and adding bracing and a crossmember either way, so my question is whether or not a high mileage one will be any different than a low mileage one at that point? Are there other parts that wear down after a 100k+ miles? I see ones on crashed cars with around 150k miles on them for less than a grand often, but the lower mileage (but also stock) ones go for closer to 2k. Is it worth it to spend the extra on the lower mileage one for what I'm doing to it?
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- Mar 2, 2015
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I have experience with the cobra IRS. If you're going to buy a used one that's not in a car running it would be best to get the rear gears rebuilt. With it out of the car its not terribly expensive. Check the axle boots for rips and cracks. The only way you know for sure what you have is to open if up. If you go that far you might as well build it... 3.73 gears and such. Try to get all the brackets and bolts. The rear shocks are a plus. The cobra shocks take a bigger bolt that goes through the lower control arm. Buy the higher mileage one out of a non wrecked car with the brackets and good axles. Replace the bushings, wheel hub bearings, and put a gear set in it. If you change the gear ratio from what your original rear had you'll have to recalibrate your speedometer.
- Mar 2, 2015
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Mileage doesn't really matter...I remember people breaking half shafts with only 20k and a lot of bolt on horsepower. You do want to stay away from rears out of wrecked cars. With so many bends in the cradle its hard to tell if it was tweaked. I always replace the hub bearings because they're cheap and easy to change. You can spin them and check them first. Age or mileage doesn't make a difference with our cars....its how much abuse they've been put through that matters.
Thanks, so just to be clear, in order to take a used IRS and make it into something that could take around 450whp, I would want to replace all the bushings, the hub bearings, maybe the gears themselves, and add bracing and a cross-member? If I wanted to put that power into an IRS what type of bushings would I want to get? Aluminum, delrin?
