I remember someone commenting about bolt-in 8.5" 10-bolt (I believe it was a narrowed 4th gen rear) conversion on this forum some time back but haven't been able to locate the thread. I need to get rid of my problematic 9-bolt and don't want to dump $2K on a 9" or 12-bolt conversion. Does anyone know of the vendor?

 

There are no 8.5" bolt in diffs except for a Dana 44. Fourth gens are all 7-5/8" diffs. The only aftermarket choices are 12 bolt or Ford 9".

If you want to fabricate some other type of rear suspension instead of the torque arm system, you can install whatever diff you want.

 

Here you go.

http://www.amazingmechanical.com/

But for the price of these, (I have looked into them, $1700.00 or so) it would be cheaper to have an impala SS rear narrowed and brackets mounted by Currie (about 600-800 or so). I am looking into seeing if Strange will do it because they are only an hour and a half away from my home and I can save a couple hundred in S&H of the rear buy driving it to them vs. shipping it to currie.

I am only using the 8.5 ten bolt I have because it was free, and it has a clutch type posi with 3:73 gears and only has a few hundred miles on it.

 

Niether Moser or Strange will touch it. They want to sell me a 2500.00 rear end and I am not buying. Moser said they will narrow it to the right length for me and redrill my axles and rotors for the smaller bolt pattern but they claim that they cannot weld the brackets on because they have no way to do it. Sounds like to me. Thats OK I will do it myself.

 

Not to threadjack, but are Dana 44s a direct bolt in, no narrowing, modifying the suspension, no welding, nothing? THX

EDIT: Also, what cars/SUVs came with these?

 

The over the counter bolt in Dana 44's were available from GM performance parts and SLP back in the day.

They have been discontinued for some time now.

However, they do show up here on classifieds and on ebay every now and then.

For a useable rear your looking at around $1000 or so to pick one up.

Its a nice setup if u can find one. I have a friend who recently acquired one and its alot beefier than a stock rear.

Wonder if a vendor would step up with a bolt in 8.5 10 botl rear(GM style)

Sure would be nice and everything is out there including 32 spline axles.

later
Jeremy

 

That's what this whole thread was about and "my3rdgen" gave us a link to the vendor we seek!

 

That still doesnt qualify as bolt in to me.

Looking at the pics and jusding by the torque arm, you have to go with their torque arm, which makes it more expensive.

No reason going to a 10 bolt should cost that much. At that much $$$ i would just go to a 9 inch or 12 bolt

I am going to email them and see what I can find out however and/or see if I can get some more pics/info

later
Jeremy

 

If you can't afford to do it right the first time can you afford to do it again?

- Dana 44 or 8.5 10-bolt would both be a waste of money in my book. Neither is really much, if any, stonger than a 7.5/7.625 10-bolt. So why? If you need stronger, then run what you have until you can afford a good rear(as in 12-bolt or 9") - You can get upgraded everything for the 7-1/2 10-bolt and, from personal experience, it's stronger than the old 8-1/2's were. So either go that route or wait until you can afford to buy better. Spending any money on something that is only possibly slightly better is a waste.

 

Opinion noted.

 

Quotes from CHP mag. tech article #48518

<"Sure, you could bolt in a 9-inch Ford, but there is a more elegant solution that’s also downright inexpensive.

GM enthusiasts assume all 10-bolts are weak. While for the most part this is true, there is one exception—the GM 8.5-inch ring-gear 10-bolt. The truth is the 8.5-inch 10-bolt is almost as strong as a 12-bolt since its ring-gear diameter is only 0.375 inch smaller than a 12-bolt (8.50 versus 8.875 inches) and the pinion gear shaft is an equal diameter. Even better, the 8.5 rear axle assembly was the universal rearend for millions of GM cars and trucks from 1971 through 1996. This means there are a bazillion to choose from


How strong is the 8.5-inch 10-bolt? Well, let’s put it this way: Both Dave Henninger and Kurt Urban run these 10-bolts (with spools) in their respective Camaros. Henninger has run as quick as 8.68/151 mph, while Urban’s Camaro runs 9.20s/145. Henninger has never broken a gear and has logged hundreds of runs. That should settle the question of durability.">

I am not going to be running 8.68/151mph any time soon, however, I do want to take it to the track and flog it with sticky tires or slicks and still be able to take it home in one piece.

 

I have a GM thirdgen Dana 44. I want to rebuild the posi but don't know who makes the unit. I found little chunks of it in the oil. Does anyone know which posi these came with?

 

I agree that a 8.5 is plenty strong I run one in my 2nd gen with a BBC with N20 and around 800 HP (has run as fast as 10.80) and never had any issues with it in many seasons of street /strip duty... but it probably would be a tough call to make one to fit in a 3rd gen without doing all the fab work yourself to save the cash outlay you would spend on a 9" ...

 

8.5 can take a royal doo doo beating :-)

Just look at any Turbo Buick :-)

And before someone goes blah blah blah, they dont shock the tires the same way blah blah blah. They run Trans brakes and launch on serious boost :-)

There also heavier than the comparable thirdgen too.

I dont know whay a complete Dana 44 used for a posi over the counter back in the day, but a friend who recently got one and it has an Auburn in it. I cant verify that it left the factory that way however.

later
Jeremy

 

I just got a factory 7.5 inch 10 bolt from a friend for free and a second gen 8.5 from him for $20.00.

When my hand and elbow heal (carpal tunnel and cubital tunnel surgery 3 weeks ago), I will start this project, take picks and post in a new thread (don't want to hi-jack this one anymore than already). I think I can get the housing done for $100.00 total with torque arm mount and an axle brace, find a used gear (if needed, don't know what I have right now) and posi for 200 to 250, rebuild kit for 125, and new axles for around 300. My drum breaks will bolt on, and I really don't need disc breaks so I am not worried about that upgrade.

Grant total is not expected to be over $800 to $900. $1000.00 with TA cover. That's half or less what I would have in a 9 inch or 12 bolt and depending on what I have to give for the used parts could make it even less.

EDIT: The $1000.00 saved can go toward FI.

 

Does the auburn have any kind of markings stamped on it?

 

??HUH??? An 8.5 is WAY better than a 7.5. I know plenty of guys running cars into the low 10's an even into the high 9's with 8.5 rears. I dont know of anyone that has had any luck with a 7.5 running anything faster than maybe 12's in the 1/4