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Discussion Starter #1
Can I use my 8.5 inch 10 bolt for racing if I rebuild it?? I know the strength comes from the spline. I have 350ci with 450 Hp. So what spline and diff. do you guys recommend? Do I need c-clip eliminators?? This is going to be my daily driver so what gears do you guys recommend? My first gear ratio is 1.52. I have a th350 with a planetery gear system and a 2800 stall convertor. Trying to learn as much about rear ends as possible. My rear end is a 3.08 one wheel wonder and I want to rebuild it myself. Thanks guys
 

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You probably won't break a stock 8.5 with 450 horsepower if you aren't using a brake and don't have a 5500 converter or something like it. I'd go with 3.73s for the balance between street friendly driving and going fast, but it helps to know the tire choice (height).

Kev
 

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Discussion Starter #4
Tire size right now is 245/60/15R. My cam is 234 int/244 exh @ 50, .520int/.544exh lift, lobe seperation is 114.
 

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Discussion Starter #5
I want to put 255/45/17R's later
 

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71Novacaine said:
Tire size right now is 245/60/15R. My cam is 234 int/244 exh @ 50, .520int/.544exh lift, lobe seperation is 114.
IMO with that cam you would want at least 3.73 gearing and possibly higher to get the best performance outta the cam. I just looked at two different books and for a cam with that much duration @ .050" one recommends 3.73's to 4.56's and the other recommends 3.90's to 4.50's. The convertors that both books recommend are in the 2500rpm-3500rpm stall range....good luck:)
 

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July's issue of Chevy HP rag there is a Q&A in the tech section from a guy running a big block 72 Nova with an 8.5 asking the same thing. The guru's state the 8.5" is a strong rear as is and one properly prepared including C-clip eliminators, aftermarket axles, rear cover with load pins over the main caps and axle tube braces has gotten many drag cars into the 8's! For peace of mind you could replace the the stock axles ( 28 spline would be fine ) c-clip eliminators, add a decent posi and you are good to go.
 

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Discussion Starter #8
Okay Thanks alot guys I got the convertor covered. I will let you know how the progress goes. Thanks again.
 

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Your 8.5 will hold up well. Here is a link to Moser Engineering with a calculator to calculate torque to the axles so you know what axles to purchase. They also have other great info. http://www.moserengineering.com/Pages/axletech.html

I went Moser 33 spline axles, spool, rear cover, ford housing ends, etc. I knew I would be adding more power in the future.
 

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LIke most said I think that you will be fine with the 8.5. If you don't change axles I would change your wheel studs. The 8.5 will take a bit of abuse before they give up. But before you start throwing alot if money at it check the price difference in getting a 9" for it.
 

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Discussion Starter #11
This is why I love this site!! Great info all the time. Thanks Guys
 

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Discussion Starter #13
Nate 104!! Thats a great article
Good find
Thanks Bro
 

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I hear about alot of people puting c-clip eliminators in their posi's. What's the purpose of that?

I'm just curious because I'm getting ready to swap out the carrier in my 8.5 with a posi 3.90 and want to make sure I have everything before I start. I bought the rebuild kit from Summit and new axle bearings, so now it just needs to be done.
 

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Discussion Starter #15
I hear that the c clip is weak and you put the eliminator in there for strenght. Thats what I heard.
 

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My daughter runs a 8.5 in a 75T/A , it's a heavy car, we run around 470 hp in a SBC motor, turbo 350 and the rear has 4:10's,, she uses a Hoosier 28x10x15 slick.. We only burned out a clutch in the burn out box one day because the box was dry..

And the C-clip had a bad habbit of wearing out and then losing the axle, usually on the road.. Or if you exploded the spider gears..

The C-clip eliminator is pressed on the end of the axle to be used like a
ford 9" rear.. The only down falls are you have to trim the ends of the housing to bolt it up ( so you ruin the housing) and they tend to leak with street use very fast..But it is a saftey factor, they usually don't lose axles..
 

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Discussion Starter #17
I won't be using c-clip eliminators for my street application then. Thanks for th info
 

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C-clip eliminators are a safety item-rulebooks say where they can and can't be used-(I forget the details).If you do happen to break a C-clip axle, there is nothing to keep the axle from leaving the car!! It can get ugly in a hurry!
I believe Strange makes the only one that can be used for street/road race applications. I wouldn't use anybody else's kit because they won't handle side loading(cornering) Mine began to leak like crazy a couple hundred miles into the 99' Power Tour--of course they were still leaking up until I just recently swapped rears! The backside of my wheels are kinda crusty!
If you don't intend to take the car to the track, don't bother. But if you do...............
 

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Discussion Starter #19
I do plan to run it on the track a little later so I won't for now. But in the future I may. Depending how bad I get the itch for more power. Is it ever enough??? HAHA :confused:
 

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Moser makes 9" style ends that use a pressed on large 9" bearing and you can run the stock 10 bolt brakes. You will have to order 9" style axles w/the chevy lug pattern and center locater but if new axles were getting purchaced anyways its not that bad. With the ends and axles w/bearings studs and retainers it's like $100 more than getting new moser axles w/c-clip elim. Way stronger and dont leak. Good time to upgrade to 30 spline as well. We do this alot on chevy's and a like type conversion on the newer 5.0 mustangs.

Miles:D
 
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