Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 20 of 39 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I have a 82' and i was wondering what could be done to this rear end to make sure it will stand up to about 450-500hp. I will running a automatic but I love to do burnouts.
 

·
They call me, Hugh Huffner
Joined
·
584 Posts
Best thing you could do is have a ford 9in modified to go in. There are companies that do this to install them in race cars, and even to stuff them into a Jag multi link for Cobras.

The aluminum case is the weak part of the diff. No matter what gears you have, axles, or clutches, or posi unit...if it grenades, it is done, at $1200.00 a whack. (899.99 from mid america, +300.00 core +shipping)

The internals can be strengthened, but the weak link will always be the case...something lets go in there she, is DONE.

A few of my friends have been through this, with high horsepower (and abusive stuntwork, lol) They tried a multitude of things, but in the end, until they replaced it with a Strange, or a drag prepped 9 in....same result...as the Germans would say...KAPUT. (then Cha-ching at a Corvette supplier.)
Steve
 

·
Supporting Vendor
Joined
·
3,770 Posts
You could convert to an iron unit that is built much stronger with some mods it will handle it. I build the iron units but won't touch a 80-82.
 

·
Supporting Vendor
Joined
·
3,770 Posts
The older unit are a lot better then the 80-82's. They can be built several ways to add strength to them, I do custom builds a lot and can offer you some pointers on what to look for.

Here is a custom job I did. Those of you familar with these will notice there are no springs in the posi. Also the case is radiused and polished to cut down on stress risers.

You can convert to these but you'll have to get the bracket for the front.

 

·
Registered
Joined
·
1,038 Posts

·
Registered
Joined
·
126 Posts

·
Registered
Joined
·
596 Posts

·
Registered
Joined
·
126 Posts
Now, when did they stop putting in the old iron?? I have a 75. Does that have the good case or the weak case?
 

·
Registered
Joined
·
596 Posts
Now, when did they stop putting in the old iron?? I have a 75. Does that have the good case or the weak case?
I understand that iron thru and including '79 (minor-differences thru the years, but basically the same ), with aluminum Dana-44 '80-'82.

The guy who installed the 3.73s in my Dana-44 a few years ago, who has lotsa experience with C3s and drag-cars, suggested not putting even sticky tires on the back of my '82, even-with the wimpy Cross-Fire, he was so scared of it:
VanSteel claims their back-dated/Dana-44 set-up is good to 650 HP with slicks, more-than-enough for my application.
:thumbsup:

Now..... if somebody would only make a spool for these cars.....

:huh:
 

·
Supporting Vendor
Joined
·
3,770 Posts
63-79's used iron units. The 63&64 used a dana posi and they were weak. Most by now have been replaced with a Eaton. 65-79's used Eaton posi's.
Posi became std in 70 and there were some open diff in the earlier models. The 65-70 posi clutches were solid steel and the 71-79 were slotted clutches to try and resolve the common hammering they have. This didn't work and the clutches break under constant load.
The 65-69 cases were prone to cracking and breaking apart,again under load. The later 70-79 cases are much better as are the service cases. The current 63-79 eaton loaded cases come with heavier springs, fiber clutches, and powdered gears. Other then the bare case they are not what I'd use.
The best built 63-79 unit is a custom built one using the best parts, that is what I do. Steel bearing caps and solid sleeves can be fit to them to increase the strength as well. There is no way a $600 advertised job will have these features so do some research if anyone is looking to exchange, you may not get what you expect for the much lower cost.
 

·
Registered
Joined
·
126 Posts
I can do this stuff myself...for the most part.. So what you are saying..I keep my case then what? trim it out and put the 12 bolt gears in like the custom job from the mag article? or keep my gears and just upgrade the carrier to a quality built posi-trac unit and put in steel end caps.
 

·
Supporting Vendor
Joined
·
3,770 Posts
I can do this stuff myself...for the most part.. So what you are saying..I keep my case then what? trim it out and put the 12 bolt gears in like the custom job from the mag article? or keep my gears and just upgrade the carrier to a quality built posi-trac unit and put in steel end caps.
How much power are you thinking of ? If you build one like the one I pictured, it will be pretty strong. It will be better then any stock rebuild for sure. Will it handle a lot of trips on the track with slicks-??? Hard to answer. The 12 bolt setup that Tom's builds is about the best vette diff out there. The one I pictured is still a 10 bolt but is a pretty good one.

I stock all the parts if you need them, just PM me. To build one you're going to need access to a surface grinder.
 

·
Registered
Joined
·
126 Posts
How much power are you thinking of ? If you build one like the one I pictured, it will be pretty strong. It will be better then any stock rebuild for sure. Will it handle a lot of trips on the track with slicks-??? Hard to answer. The 12 bolt setup that Tom's builds is about the best vette diff out there. The one I pictured is still a 10 bolt but is a pretty good one.

I stock all the parts if you need them, just PM me. To build one you're going to need access to a surface grinder.
I'm planning 650 at the flywheel...don't plan to be at the track too often...I have a friend who does custom Jeep builds and has a full machine shop..
 

·
Registered
Joined
·
706 Posts
I have an 82 with an LS1 and a T56. The motor is putting 400hp to the wheels. So is my stock rear end not going to hold up? I was just going to buy all new gears and carrier and posi from Toms. But with the aluminum case I will still probably have a problem? How much do you want for one of your steel conversions?
 

·
Registered
Joined
·
5,916 Posts
I have an 82 with an LS1 and a T56. The motor is putting 400hp to the wheels. So is my stock rear end not going to hold up? I was just going to buy all new gears and carrier and posi from Toms. But with the aluminum case I will still probably have a problem? How much do you want for one of your steel conversions?
That would depned on tires (traction) and how you drive. If your getting ready for a gear change, etc., I think I would change it at this point.
 

·
I support glass stairways
Joined
·
5,955 Posts
You say you love to do burnouts, why don't you just run a "cheaper" harder compound tire, that way the tire breaks loose before any of the rear-end parts are under too much of a load. You'd still be able to use all of your power through mid and top-range but down low you'd have to feather the throttle. Are you intending to use this car strictly for drag racing or is it going to be a street car? If it's to become a drag car then you will want to just install a straight axle 9", if it's to be a street car then just buy harder tires, that is what I would do, actually that is what I have done. Let's face it, if you've got that kind of power on the street you can afford to allow your opponent to have the hole-shot, only for you to blow by him like he's going backwards afterwards, plus, you can put on quite a show if you want to. I've got half the power you are expecting and I have TONS of fun with my 'vette on the street.:thumbsup:

EDIT: BTW, I run Kelly Charger tires, usually about 90 bucks a tire w/ mounting and static balancing, they put off great smoke and hold well in the corners. If you want proof of the smoke they put off just let me know.:cheers:
 

·
Banned
Joined
·
1,873 Posts
the iron diff bolts up the the alu batwing, but you do need to swap out the camber rods and bracket as you now need to use the earlier model stuff. Also, you need the earlier halfshafts. You can also upgrade to the 12 olt stuff but then you need to notch the batwing to clear the drive flanges. No big deal really.
 
1 - 20 of 39 Posts
Top