A New and Affordable Way to Bulletproof IRS?

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C3 IRS (Independent Rear Suspension

We live in a world where horsepower is plentiful, but an older Corvette’s IRS needs some beefing up, and our forum may have the answer.

Modern Corvettes that come from the factory with a ton of torque are constructed to stand up to that power. However, if you’re looking at building a 7-8 second C3 then huge power + weight + traction = breaking stuff. There’s no escaping it, you’re going to need to strengthen things up.

That’s what CorvetteForum members Tumarr and Hiltonlo are taking a crack at. Of course, money solves all problems but, with a little help from the community, they are trying to do it without breaking the bank. They are aiming for the $3000 mark for parts and materials. Fabrication is expensive unless you have equipment, time and skills already, so bear in mind that individual mileage may vary.

Tumarr already has form with a fast C3. This is a video of his fully built car that’s gone long past having independent rear suspension.

In the original post, Tumarr points out the 12 bolt conversion is an excellent solution, but modern Mustangs are out there running 8’s with stock IRS. As a starting point, the 2015 and onward Ford 8.8 differential looks like a solid go-to. Shopping for them used gets them for around couple of hundred bucks under the retail price of $720.

Tumarr and Hiltonlo’s  initial concept starts with the Mustang IRS differential, a pair of 2014 and up C7 Corvette rear hubs and custom made CV Axles. The 8.8 diff and the C7 hubs bought new only add up to a little under $1000. Custom made CV Axles are a lot more expensive though, and the price depends on the amount of power expected to go through them. However, the builders and the community have lots of ideas and possible options to keep the price down.

The project is ongoing so do go and join the thread and follow along. These guys are forging a path that, no doubt, many will follow.

Ian Wright is a regular contributor to Corvette Forum and 6SpeedOnline, among other auto sites. Check out his podcast Both Hand Drive.

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