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I know nothing about what it takes to build a strong Corvette independent rear differential.
There are numerous threads about building a super 12 bolt rear differential for racing, but nothing I've found really lays out what it takes to build a rear differential using the OEM differential case as a starting point.
I would like to open this thread to those who build performance differentials and those who have had a differential built that has held together under street or occasional track days usage.
It would be great to have the components and parts named with the manufacture.
I know this will open up a lot of discussion about what works best and we all know how many believe their opinion is the only way, so, I would like this thread to be more of an educational thread that could be added as a "Stickey" for those like me who know nothing and need to learn.
Using my build as an example:
I'll be running a 496 cubic inch, putting out an estimated 630+ foot pounds of torque and a TKO-600RR transmission with 3.36 gears.
I plan to use my Corvette for highway cruising, some spirited driving, mountain, coastal and foothill winding roads.
So, how would you build it using "top quality components"?
Posting photos is always nice.
Thanks, Greg
Most everyone uses the factory 10 bolt case, both the Super 10 bolt and 12 bolt builds are using the factory rear end case. The "12 bolt" build requires extensive machining of the inside of the factory case to make the 8 7/8" ring gear clear. By doing the 12 bolt build, you have a bigger, stronger ring gear and a much better posi case (and more posi case options). For a stick car, especially if you're planning on running some drag radials, the 12 bolt is the way to go. You can expect to spend upwards of $7k for a full 12 IRS build with all of Tom's goodies, HD half shafts etc.... Down side is, 3.70 is the tallest gear ratio available for a 12 bolt.
The "Super 10 bolt" build basically keeps the stock 8.2" ring and pinion, as well as the stock posi case, yet its fitted with 12 bolt spider gears, cross pin and posi clutches. The housing is machined for a big steel cap for the left side. Usually Toms 30 spline inner axles and 31 spline outer axles are used. Typically the clutch packs are "tuned" which means they are shimmed to spec and not using springs for preload. 3" shafts and 1350 u joints are common. This combo is proven to hold up pretty well in automatic cars with 600-700hp. This setup is typically about $5k. Gary Ramadei (GTR1999) and Mike Dyers (Tracdogg) are the two best builders of either of these IRS combos in the country.
There is a lot more details to both of these combos, this is just the high lights.... Get that check book out...
Wasn't there a pricey, commercially available C3 diff & housing based on Ford 9" ?
Ridetech sells a 9" IRS variant (system is around 10k), and Detroit Speed & Engineering has a 12-bolt variant (close to $15k in their system if I'm reading the site correctly).
It's worth noting that these are complete suspension systems.
Last edited by Shark Racer; 01-20-2019 at 07:27 PM.
Most everyone uses the factory 10 bolt case, both the Super 10 bolt and 12 bolt builds are using the factory rear end case. The "12 bolt" build requires extensive machining of the inside of the factory case to make the 8 7/8" ring gear clear. By doing the 12 bolt build, you have a bigger, stronger ring gear and a much better posi case (and more posi case options). For a stick car, especially if you're planning on running some drag radials, the 12 bolt is the way to go. You can expect to spend upwards of $7k for a full 12 IRS build with all of Tom's goodies, HD half shafts etc.... Down side is, 3.70 is the tallest gear ratio available for a 12 bolt.
The "Super 10 bolt" build basically keeps the stock 8.2" ring and pinion, as well as the stock posi case, yet its fitted with 12 bolt spider gears, cross pin and posi clutches. The housing is machined for a big steel cap for the left side. Usually Toms 30 spline inner axles and 31 spline outer axles are used. Typically the clutch packs are "tuned" which means they are shimmed to spec and not using springs for preload. 3" shafts and 1350 u joints are common. This combo is proven to hold up pretty well in automatic cars with 600-700hp. This setup is typically about $5k. Gary Ramadei (GTR1999) and Mike Dyers (Tracdogg) are the two best builders of either of these IRS combos in the country.
There is a lot more details to both of these combos, this is just the high lights.... Get that check book out...
Good summary. 69ttop502 has a 10 bolt with the best of everything and has similar build. Maybe check out his thread for reference to get an idea of what you need.
I was lucky enough to work directly under Mike Dyer (Tracdogg2) as he gave me full access to his shop and three days of his time to teach me and walk me through rebuilding my rear end myself. I’m also lucky enough to be able to retain everything I learn hands on so if I ever have to do it again in my own, all I need is access to the right equipment.
I will not go into detail about everything we did to my rear end here (not sure what things are his special secrets) but I can’t tell you how happy I am with this rear end. 6k miles on it and I’ve beat this thing hard under 500 ft/lb launches. Still as quiet as can be.
I can’t say enough good things about Mike. He’s the man for the job if you want someone to do it, imo.
-Stroke
Last edited by Strokemyaxe; 01-20-2019 at 11:55 PM.
I know nothing about what it takes to build a strong Corvette independent rear differential.
There are numerous threads about building a super 12 bolt rear differential for racing, but nothing I've found really lays out what it takes to build a rear differential using the OEM differential case as a starting point.
I would like to open this thread to those who build performance differentials and those who have had a differential built that has held together under street or occasional track days usage.
It would be great to have the components and parts named with the manufacture.
I know this will open up a lot of discussion about what works best and we all know how many believe their opinion is the only way, so, I would like this thread to be more of an educational thread that could be added as a "Stickey" for those like me who know nothing and need to learn.
Using my build as an example:
I'll be running a 496 cubic inch, putting out an estimated 630+ foot pounds of torque and a TKO-600RR transmission with 3.36 gears.
I plan to use my Corvette for highway cruising, some spirited driving, mountain, coastal and foothill winding roads.
So, how would you build it using "top quality components"?
Posting photos is always nice.
Thanks, Greg
Thanks for starting this thread. I will need to do mine soon as well.
I just finished mine with info from this forum and others. It was my first build and lots of fun.
Lightly used Eaton posi, polished
17 spline spider gears from same posi, deburred
timken bearings throughout
Tom’s crossshaft
Tom’s bearing cap
US Gears 3.73 lightning polished gearset
Used 66 case from eBay coated with POR15
Muskegon HD cover
HD 17 spline axles from Corvette International
steel clutch kit
Dennys Driveshaft pinion yoke
ARP ring gear bolts
Tom’s cap screws for bearing caps
I called Tom's and talked with his wife.
At this time they are not building units, however they are still producing and selling the parts that made their rear diff's so good.
They recommended both Gary and Mike to do the actual work.
I am trying to get a list of the necessary parts to build a solid unit so I can send them out with my rear diff to one of the recommended builders and have them build the unit for me.
It looks like Dragvette is selling their own "Racers Rear End" with 30-spline inner axles, 30-spline spider gears and larger center pin. They're even manufacturing their own 30-spline inner axles they claim are better than Tom's (thicker flange), also US made. Anyone tried their stuff yet?
01-20-2019, 03:09 PM
What Does It Take To Build A Strong Rear End
