Freakazooid52

iTrader: (1)

Ive heard about buying a 9" in center like this currie one from jegs 272-92000 do I just have my old center part cut out of my 7.5 and that housing welded in with a center section from the junkyard toi make a 9" for my firebird?

please tell me its not that easy..., there something im missing?

anyone have more info on this? the search wont work for some reason

sofakingdom

iTrader: (1)

OK...

It's not that easy.

No you can't use your 7½" guts. You need Frod 9" guts.

I don't think "search" is required for that.

xpndbl3

iTrader: (5)

you can purchase a junkyard center out of a 80s bronco for instance, a lot of them had 4.10s and posi. You'd need one with 31 splines to work with the $1000 moser housing and axle package. Which still means you'd need brakes as well, and after all this extra effort to mismatch parts you're left with expensive junkyard pieces when a brand new one wouldn't be more than a 500 more than the junkyard route.

AlkyIROC

That Jegs 9" center housing is for building a complete new diff. Nothing from your GM diff will work. That center is for those who don't want to use a factory center housing. New axle tubes need to be installed and welded in which requires an alignment jig. After that, the axle ends need to be welded on. A 9" center section is bolted into it and custom axle lengths are ordered. This is only for someone making a custom differential for something like a dragster or a back halved car.

What you need is a bolt in 9" housing with axles which is available from many different suppliers. It includes the housing which is designed to bolt right into a third gen and a pair of axles. To use a junkyard center section like mentioned above, you can find factory ones for 28 or 31 splines axles. Find a center section first to know what spline count it is then order the housing package with the axles in the proper spline count. Ford 28 spline axles are still stronger than GM 28 spline axles. You'll still need to fabricate a brake package.

Buying the housing and axle package is around $1000. Finding a junkyard center section varies but expect to pay around $150. You'll have to decide how to fabricate a brake system. I use Ford drum brake and use the Ford bolt pattern on my 9" to make a simple brake installation.

You can also buy a complete, new, ready to install, 9" differential, just add oil for $2500 - $3000

Freakazooid52

iTrader: (1)

WOAH, I knew it couldnt be that easy, thanks for the info

Im going to order a moser housing/axle package for 985$ one made for the f-bodys with a torque arm bracket, when ever i find a center section.

thanks for the help guys, my 7.5 rear blew two days ago I wasnt even getting on it, lol.

are stock 9" center sections still pretty beefy to live behind a 350 with some burnouts here and there some red light drags and passes down the track?

sofakingdom

iTrader: (1)

Stock center sections are stronger than 7½" or 8.2" 10-bolts, but nowhere near a 12-bolt. Unless you can find one of the nodular iron ones (has a big "N" cast into it), which are MUCH better than the otehr stock ones. But those are getting really tough to come across because everybody who knows what they're doing has already long since scarfed them up. Then there's the variations in axles, length, brakes, and so forth. There's ALOT more to it than just go the buzzard and snag the first one you see and 10 minutes later you're driving it around.

The Frod 9", as it comes from Frod, is not a particularly "heavy-duty" piece at all. The beauty of it is in the AFTERMARKET support for the PLATFORM. The reasons it became so popular are NOT because it was some kind of bulletproof indestructible thing; it's because it makes a great "quick-change" setup (unlike, say, a 12-bolt), and it used to be SO PLENTIFUL and CHEAP, you could find literally heaps and piles of them in junkyards waiting to be melted down so they were almost free, you could buy a half-dozen of em and mix & match to come up with what you wanted and if you tore it up you could always go back and get another half-dozen. Think of it that way, not as a ready-to-run heaven-sent answer to all your problems; it's just about like your 350, you wouldn't just go to the junkyard and get just ANY 350 and slap it off into your car just like it is and go out there and expect to do battle with the best of em on the race track. The 9" is about the same way. Sure, it's big and heavy and all that, and you can buy all sorts of great stuff that FITS it; but it's still just yerbasic stock passenger car or light truck junk part.

xpndbl3

iTrader: (5)

sofakingdom is right....key word is LIGHT duty rear end. These came in half tons, not 3/4 ton or 1 ton trucks. The factory pieces are stronger than the thirdgen rears, but that isn't saying much. Will it last behind a stock 350, sure but add in slicks, nitrous, etc and you're on borrowed time just like a typical 10 bolt.

AlkyIROC

I run aftermarket 31 spline axles in my narrowed 9". With the powerglide's 1.76 first gear, I don't have to torque multiplication where I would need 33 or 35 spline axles. I have a spool with the small side bearings. I have the smaller 28 spline pinion gears. I still use a factory 7AW case and pinion support and it's all still surviving.

I will be upgrading to a bunch of aluminum parts just to shave weight off. I have an aluminum spool and pinion support but haven't picked up an aluminum case yet.

Freakazooid52

iTrader: (1)

okay, so all I need is a bolt in housing with axles for my F-body, a center section from something and its a working rear?

Im gonna use the junkyard center section just as means to have the car move, its still my DD. later i will buy a aftermarket one.

Anything else im missing (besided changine the yokes/ujoints around i can figure that out)

Bolt in housing+center section+brakes=a working rear end?

AlkyIROC

Find a junk center section first. If you're lucky enough to find a factory posi, you'll need to know what the axle spline count is. It will be 28 or 31 spline. Then you can order the axle housing package. It will come with axles in the 28 or 31 spline count as you require. No sense ordering a 31 spline axle package when you can only find a 28 spline carrier.

You may not find a posi but most trucks and vans will have 3.00 to 3.50 gears. I walked into the local PNP yard a couple of months ago and stumbled across a Bronco that hadn't been stripped yet. I picked up a center section with a 31 spline factory posi and 4.11 gears for less than $100.

RAPIDFIRE

hi

RAPIDFIRE

hi
my 9 inch ford
2 axles moser bolt pattern 4.50 $290 dll
1 detroit locker $480 dll
1 diferentiall used f100 year 72 (28 spline,open carrier) $50 dll
1 kit bearing axles $60 dll 1kit bearing intallation gear $89 dll
1 video instruction ring - pinion $15 dll
$$
1 life happy my 9 inch

RAPIDFIRE

hi
my 9 inch ford
2 axles moser bolt pattern 4.50 $290 dll
1 detroit locker $480 dll
1 diferentiall worn f100 year 72 (28 spline,open carrier) $50 dll
1 kit bearing axles $60 dll 1kit bearing intallation gear $89 dll
1 video instruction ring - pinion $15 dll
$$
1 life happy my 9 inch