what do people recommend buying when looking for a used rear end. i heard the 9in borg warner that has a 3.42 and posi was good any comments?

 

little off way actually way off. It is not a 9 " borg warner it is a 9 bolt b/w and 10 bolt. there is a huge difference in the 9 bolt and 9" the 9 bolt is better than the 10 bolt but is alot more expensive and harder to get gears for. If you are investing $1000 in the rearend then get a 9" with the right brackets and the torque arm mount. If you were around Ohio a friend of mine has a 9 bolt with 3.45's (I think, I can check for sure) I am not sure how much he wants for sure I think $350

 

that's what i meant sorry i know the difference between a 9in and a 9 bolt.
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anyways i'll have to get back with you on your friends. do you know if it has drums or rotors?

 

disc but I don't think he kept the prop valve. so you would have to get an adjustable one or a used one.

 

WHAT DO U MEAN THE PROP VALVE

 

if you currently have drums you will need a proportioning valve. I just didn't feel like spelling it all out.

 

oh

 

do you know what there is all to do when converting to disk brakes in the back

 

what exactly does the proportioning valve do and where do you mount it on the f-bodys?

 

it is near your brake booster. change rearends and the prop valve. bleed your brakes. drive. also if you are interested I am in NW Ohio.

 

i'm not to fimiliar with rear ends is the borg warner ones the best for the 3rd gen out of the 9bolt? also is your friends rear end posi? and what kind of shape was it in when he took it out?

 

It was in my 87 iroc. he helped me tear it apart and he wanted it. yes it is posi and there was almost zero wear on it. great deal. I just didn't have room for it or I probably would have kept it. also all 9 bolts were borg warner rears.

 

i've been looking more and more into swapping a 4th gen rear in my car. it sounds pretty similar to what i already have to do.

 

4th Gen rear axle assemblies will bolt in but do not exactly fit because the axle tubes are longer. You would have to use wheels designed for a 4th gen car, too. That would require large wheel spacers on the front which is a really really really poor idea. It's tough on bearings, wheel lugs, and negatively impacts handling. You only have 3 options for OE (original equipment) rear axle assemblies.

1. 10 bolt "Saginaw" axle assembly. I presume it was built in Saginaw, Michigan. Most commonly used and not very strong. I would limit power output to only 300 Hp. Some people have luck beyond that level but it's just that... luck.

2. 9 bolt "Borg Warner" axle assembly. It was built by Borg Warner and I think sometimes it's called an "Aussie" rearend. Not so common an option. Stronger parts generally good for 400 Hp. It does come with disc brakes so that's a nice feature if you don't have discs today. It comes in a wide range of gear ratios.

3. Dana 44 from '89 Turbo Trans Am. You probably won't find one but you need to know they exist. Probably considered the best factory rearend and well supported by the aftermarket business due to common use in 4x4 trucks.

Any other rearends out there are aftermarket versions and are very expensive. Our cars are unique in that the "torque arm", part of the suspension system that keeps the rearend from rotating, is mounted between the center section of the rear axle assembly and the transmission tail housing. Camaros/Firebirds are the only cars built like this so it makes rearend swaps from other cars difficult. You can't just grab any rearend and put it in. You have a couple options in the aftermarket. All these will come with larger input yokes and you will have to use larger bearings on your driveshaft.

1. Chevy 12 bolt. Many companies make the Chevy 12 bolt style rearend already fitted for our cars. This includes places like Strange Engineering, Moser, and Currie Enterprises. It transfers power more efficiently than the Ford 9-inch, but tends to be more expensive and probably not quite as tough. Although, I dare you to break a properly built unit. Don't waste your time on this style unless you are prepared to pay for C-clip eliminators. This will keep your axle from falling out if it breaks.

2. Ford 9-inch. Again, many companies make these units as mentioned above. They might be new or used (rebuilt and modified). These are tough units but have significant power loss through the gear train and will reduce your ground clearance.

3. Have a shop modify a used rearend from another car and mount proper brackets. I'm not sure you're ahead because of the custom work. And the final cost also depends on your ability to locate a decent rearend to begin with. This doesn't sound like one of your strengths at the moment. You'd be better off leaving that to professionals.

 

thanks for the input.

i was just reading many posts off this website and many people have had success. as of now i don't have stock 15 in rims i have 17in rims made by american racing. so if those rims fit on the 4th gens than i should be all set. right?

 

i know this may be a dumb question but i figured i my as well check just to be safe .

firebird and camaro rear ends are interchangeable right just like everything else on the two cars? like a 4th gen rear will fit in a 85 camaro right?

 

I don't know for sure. Never done it. I know for certain that you will need 4th gen wheels with it. Again, it's not a good idea to use those wheels on the front because you need massive spacers. Some companies don't even make spacers anymore because of safety liability.

 

for whatever it is worth you *could* just buy a 9 bolt that had the drum brakes on it and not bother with the disk conversion and needing to change out the master cylinder and the prop valve and such. My 85 came with the 9 bolt and it has drum brakes on the rear......... might be a easier way to go for you, just my 2 cents though.... so they *are* out there too....

(time to return to resident lurker now though.....)

 

is there really a difference in how much horsepower a rear can hold up to when it comes to a 3rd gen or a 4th gen rear end. ideally whats the best rearend to get. is posi from a 9 bolt 3rd gen rear end about as strong as a 10 bolt from the 4th gens?

 

supposedly stronger. but they will all fail before a 12 bolt, dana, 9", corporate 14 bolt from the full size chevy trucks. I wouldn't trust a 10 bolt past 400 horse. maybe 450 for the 9 bolt. you can get a complete 10 or even a 9 bolt for less than half of the cost of just the housing and axles for a 9" just because the 9 and 10 bolts are plentiful compared to the 9" that has to be made the right length and the torque arm bracket added.

 

so ideally a 9in from an older camaro like an 88 iroc is the way to go when doing a rear end swap.?
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also are the posi tractions in the 9 bolts just as good as the 4th gens or do they were out faster. do they use clutches. i heard the 99-02 4th gens posi lasted the longest?

 

it is all in pm if you change the fluid and inspect everything you will be fine on all of them.

 

how come so many people say you'll need spacers for the rims and tires when converting to the 4th gen rear end? aren't the bolt patterns the same on the 3rd gen as the 4th gen?