9" why

[2000dreambird]

ok maybe its just me i'm GM all the way why!!!!!i ask again why a ford 9" rear end i see people do it to there birds an ss's all the time around here is it just a MA thing don't you need to hack up the car to install it ?:vodka:

[Mr. Luos]

No hacking.

I have one. I NEVER have to worry about it.

[2000dreambird]

why don't you have to worrie about it i'm all for a good swap if i can justify it

[Mr. Luos]

Basicly as strong as they come.

I have a Moser 9", no hacking, it is a bolt in piece.

[JoshieDoom]

Bolt in replacement, strong as piss. Hacking is for PCs.

Go Dana 60 if you dont like the 9 inch. Or 12 bolt.

[2000dreambird]

i hear alot about the 9 whining hows the dana an the 12 b do

[JoshieDoom]

i hear alot about the 9 whining hows the dana an the 12 b do

All can be equally strong is set up well. The s60 by strange and the m9 by moser are the two best you can get for our f-bodies.

All are bolt in replacement.

If setup, broke in, and use correctly the rear shouldnt whine.

[2000dreambird]

i think i got 3:23 's in it now (stock) what do you think is best for street use as far as smoking most the normals around.....thanx for the info:yourock:

[ntimid8r]

I suggest you do your own research but here's my .02 for ya.

Basically the 9" is a stronger unit than the 12 bolt. For one, the ring gear being 9 inches versus the 8.875 inch in the 12 bolt. Also the 9" has a rear pinion support that helps lessen the gear deflection under high torque launches. Another plus for the 9" is the lower pinion location which provides better tooth contact. If you want to change gears with a 9", just swap the gear pumpkin. A 12 bolt has to remove the ring gears and be dialed back in which is a tedious job.

The 12 bolt is not a shabby unit by any means but the 9" is more durable. There's a few aftermarket companies that make 9" kits that are a direct replacement for 4th gen f-bodies, so just follow the directions then remove and replace. No hacking required. In my opinion the Midwest Chassis & Performance is the best 9" unit on the market today.

A 9" will cost a little more than a 12 bolt but as always, it all depends on what you can afford. A 12 bolt will do great for most all 4th gen f-bodies. If you want bullet-proof, then go 9".

[2000dreambird]

your the man that helped alot awsome detail thanx

[Mr. Luos]

I don't like how the torque arm mounts to the Dana or the 12 bolt. Break it, and the entire housing is trashed.
Break the mount on the 9"...and it is only gonna cost the bracket.

[ntimid8r]

I don't like how the torque arm mounts to the Dana or the 12 bolt. Break it, and the entire housing is trashed.
Break the mount on the 9"...and it is only gonna cost the bracket.
How many torque arm mounts have you broke on the Dana or 12 bolt? :dunno:

[Hi-Po]

How many torque arm mounts have you broke on the Dana or 12 bolt? :dunno:

Bob at EPP will tell you the same thing. Sure, its not common to break TQ arm mounts. What IS common is launching on a 12 bolt housing in a f-body setup and getting gear whine right after. Thats why, specifically, a 9" IS the better setup. For both reasons, and they go hand in hand with each other. The TQ Arm mount is in a location to where it not only has a less chance of breaking, but more importantly... wont create gear noise when subjects to a track.

[Hi-Po]

BTW. My 9" has almost zero noise. 1100 miles on it.

[ntimid8r]

Sure, its not common to break TQ arm mounts.
So if it's not common, they why paint the picture of a 12 bolt being a useless rearend? :bs: I have a 12 bolt and have made many launches and hmm there's no whine noise going on? How about posting your own experiences and not hear say.

[Hi-Po]

So if it's not common, they why paint the picture of a 12 bolt being a useless rearend? :bs: I have a 12 bolt and have made many launches and hmm there's no whine noise going on? How about posting your own experiences and not hear say.

Ok, I will post my own experiences. Lets start Rich. Moser 12 bolt. You wanna start there? I guess we will.


It whined, after 1/4 wacks and som sticky MT time on the street. Yea I had one of those also.


9". No whine. Granted no 1/4 trips yet as I just got it re-re-tuned. Ill be sure to let you know :)

And no where, did I say a 12 bolt was a bad rear. Hell, mine should have lasted forever. The fact is, that it whined, on both.... decel and accel.

Experiences.

[ntimid8r]

Ok, I will post my own experiences. Lets start Rich. Moser 12 bolt. You wanna start there? I guess we will.


It whined, after 1/4 wacks and som sticky MT time on the street. Yea I had one of those also.


9". No whine. Granted no 1/4 trips yet as I just got it re-re-tuned. Ill be sure to let you know :)

And no where, did I say a 12 bolt was a bad rear. Hell, mine should have lasted forever. The fact is, that it whined, on both.... decel and accel.

Experiences.
You're the one posting about how common it is that the tq arm mounts break on a 12 bolt like you run a shop and see it all day long. But in reality you had one Moser brand and it whined on ya. Did you contact Moser to resolve the problem? Obviously they didn't set the back lash correctly. But I still don't see you posting your experience of the tq arm mount breaking when you previously posted of how common that is.

Thanks for sharing your expert analysis though. :rolleyes:

[Firebirdjones]

I've built quite a few for people, 12 bolts and 9 inchers that is.
I've found (through alot of headache) to stay away from the moser cast 12 bolt housings. However,,from that point on, I've used Strange 12 bolt housings and had nothing but great experiences with them.

I'm a 12 bolt fan, never had gear whine issues, (once I switched housings) and never had any issues with torque arms, some high HP applications as well. I just don't see that huge casting ever being an issue. The 9 inch is a good piece as well.

As mentioned the 9 inch has a lower mounted pinion in relation to the centerline of the ring gear. That alone is what gives the 9 inch a strength advantage,,,but it also has a downfall. That is also why the 9 inch takes more power to turn it.
I'm not a big fan of the pinion supports, and that is a real weak spot in the 9 inch. It's not until you get into the high end aftermarket supports where they become worthy in my opinion. I can't tell you how many 9 inch housings I've set up and found a cracked pinion supports or inner bearing supports. In severe cases you can blow the pinion right out of the case with the driveshaft still attatched to it,,,,don't ask :chuckles:

I've never found or seen torque arm issues with the 12 bolt or 9 inch. The 12 bolt if built properly can withstand just as much abuse.
As far as setting up gears between the 2 it's not really an issue unless you are class racing in NHRA or roundy round racing where gear swaps every weekend are the norm.
As far as that goes the 9 inch has an advantage,,,that is if you can afford to have extra third members laying around at about $1,000-$1,500 a piece ready to go. :lol: The reality is though, you still have to setup those third members too, just as you would any other rearend. So don't let that be a deciding factor by any means.

So really it just comes down to what you would like to have.

[Hi-Po]

You're the one posting about how common it is that the tq arm mounts break on a 12 bolt like you run a shop and see it all day long. But in reality you had one Moser brand and it whined on ya. Did you contact Moser to resolve the problem? Obviously they didn't set the back lash correctly. But I still don't see you posting your experience of the tq arm mount breaking when you previously posted of how common that is.

Thanks for sharing your expert analysis though. :rolleyes:
:lol: Ok, thats cool. :)

To the orginal poster, there is minimal, almost zero "hacking" as you say to fit a Non GM rear end under your Fbody. If you want to keep ABS, it will be extra if you have a 3 channel rear. Some people have had to make alittle more room in certain areas for the TQ arm. Also, the bracket for the Tq arm sometimes has to be notched slightly. I didnt see any of those issues, but some have. Ill never look back from my 9". Love it.

[ntimid8r]

I've built quite a few for people, 12 bolts and 9 inchers that is.
I've found (through alot of headache) to stay away from the moser cast 12 bolt housings. However,,from that point on, I've used Strange 12 bolt housings and had nothing but great experiences with them.

I'm a 12 bolt fan, never had gear whine issues, (once I switched housings) and never had any issues with torque arms, some high HP applications as well. I just don't see that huge casting ever being an issue. The 9 inch is a good piece as well.

As mentioned the 9 inch has a lower mounted pinion in relation to the centerline of the ring gear. That alone is what gives the 9 inch a strength advantage,,,but it also has a downfall. That is also why the 9 inch takes more power to turn it.
I'm not a big fan of the pinion supports, and that is a real weak spot in the 9 inch. It's not until you get into the high end aftermarket supports where they become worthy in my opinion. I can't tell you how many 9 inch housings I've set up and found a cracked pinion supports or inner bearing supports. In severe cases you can blow the pinion right out of the case with the driveshaft still attatched to it,,,,don't ask :chuckles:

I've never found or seen torque arm issues with the 12 bolt or 9 inch. The 12 bolt if built properly can withstand just as much abuse.
As far as setting up gears between the 2 it's not really an issue unless you are class racing in NHRA or roundy round racing where gear swaps every weekend are the norm.
As far as that goes the 9 inch has an advantage,,,that is if you can afford to have extra third members laying around at about $1,000-$1,500 a piece ready to go. :lol: The reality is though, you still have to setup those third members too, just as you would any other rearend. So don't let that be a deciding factor by any means.

So really it just comes down to what you would like to have.
Good and accurate info, thanks for your post. :thumbup:

I have a Strange 12 bolt as well. I didn't want to post any negative speculations that I've heard about Moser brand. But from my research, I didn't want to go with Moser. My 12 bolt has been flawless and I pump 540 rwhp through it and no issues.

[Firebirdjones]

Good and accurate info, thanks for your post. :thumbup:

I have a Strange 12 bolt as well. I didn't want to post any negative speculations that I've heard about Moser brand. But from my research, I didn't want to go with Moser. My 12 bolt has been flawless and I pump 540 rwhp through it and no issues.

I feel it's important to get usefull information out to the public,,,whether good or bad. I wasn't the only one that had poor results from Moser, either product or customer service, I could go on and write a book but I'll just leave it at that.

Glad to hear you are happy with that strange 12 bolt. It's a stout piece.

[INMY01TA]

I have heard of 9 inches making noise too. I have a Strange 12 bolt, it makes alot of noise but has never broken on me. I'm pretty happy with it. To do all over again I'd go 9 inch tho.

[2000dreambird]

why would you go 9" over the 12 bolt

[Mr. Luos]

why would you go 9" over the 12 bolt
Plain and simply put....more stout.

I know guys in the 10's with their M6's and a 12 bolt.
I know guys that have torqued their 12 bolts housing and gotten a TON of whine, from one launch.
What I don't know is if they were Moser's or Strange's rears.


Putting a HP number down through the rearend makes no difference. I ran around on my stock 10 bolt and made 530RWHP. I knew better than to try to launch it though....
When it truly matters, is when the car launches HARD from a dig.
If you make that 530RWHP and run low 12's....the stock 10 bolt should be able to take that abuse (at least in an automatic car, the M6 beats on the rear more do too the shock of the clutch drop).
But if you are making 530RWHP and running 10's, then you are putting stress on that rearend....and that is when you want the strongest piece under the car you can get.


I do like Strange better than Moser when it comes to the 12 bolt.
I still firmly believe that a Moser 9" is better than a Strange 12 bolt when it comes to taking abuse. Everyone will have their own opinions, you need to sift through them (and do some research of your own outside of this thread, like calling Bob at EPP) and form your own.

[allbaugh_04]

I think the big question for me would be which eats more power? I've heard, but don't know...9", 12-bolt, and then the s60 eat the most power.

Also, when and if I break my 10-bolt, will I need an aftermarket torque arm with these rears? Of course I would want one, but just curious...

[shady milkman]

I think the big question for me would be which eats more power? I've heard, but don't know...9", 12-bolt, and then the s60 eat the most power.

Also, when and if I break my 10-bolt, will I need an aftermarket torque arm with these rears? Of course I would want one, but just curious...

the dana will eat the most..then the 9..then the 12 bolt...but like C said before..for most..its about the abuse of a hard launch. Also yes after market torque arm is needed most of the time..some come with. I will be going with the midwest fab'd 9 when the time comes..but i am sure i will have a torque arm by then..so whats another 300 bucks in the long scheme of things

[zmg00camaross]

I have my stock torque arm with my 9 inch. It was pretty shitty getting it in there. I don't recommended it because I think it's going to snap. it tight like a rubber band. Then I can go madman and co suspension. O and why have a 9 inch, it just looks badass underneath a 4th gen

[allbaugh_04]

ya 300 is a good chunk of change...to add onto the 2k rear end :lol:

[Mr. Luos]

Running my UMI tunnel braced torque arm. Had it on the 10 bolt, and I now have it on the Moser 9"

[shady milkman]

here (http://www.umiperformance.com/products.php?category_id=130)

i have been refering to the tunnel mount kit.

[Hi-Po]

Running a BMR TQ arm. There was actualy zero modification required to get it to bolt up. I have heard of some people having to notch the TQ arm bracket to clear some 9" and 12 bolts. An after market tunnel mounted Tq arm is a must. So is a driveshaft IMO. I went with PST, its a nice piece, but very pricey. Weighs the same, if not less then the stocker though and rated at 1000 HP.

[Firebirdjones]

Running a BMR TQ arm. There was actualy zero modification required to get it to bolt up. I have heard of some people having to notch the TQ arm bracket to clear some 9" and 12 bolts. An after market tunnel mounted Tq arm is a must. So is a driveshaft IMO. I went with PST, its a nice piece, but very pricey. Weighs the same, if not less then the stocker though and rated at 1000 HP.

That would probably be the chrome molly piece....that's all I care to run.

[Hi-Po]

That would probably be the chrome molly piece....that's all I care to run.

It costs a little more, yes. But the thing saves you in shipping cost! :)

Im happy I spnt the extra cash on the driveshaft. I actually forgot to install my DS safety loop. As long as I dont put a full slick on it, Im not worried about it.

[Firebirdjones]

It costs a little more, yes. But the thing saves you in shipping cost! :)

Im happy I spnt the extra cash on the driveshaft. I actually forgot to install my DS safety loop. As long as I dont put a full slick on it, Im not worried about it.

If you went with the chrome molly shaft along with 1350 series u-joints you are golden. Shouldn't have to worry about it at all.

[allbaugh_04]

So is a driveshaft IMO.

I should be ok...my car came with 2.73s and a steel drive shaft :yup: :lol:

[Firebirdjones]

Steel driveshafts are better than that aluminum crap GM started using.

Although the stock mild steel can twist,,,I've seen the stock aluminum shafts twist like a pretzel more often than not. If I had to make a choice on stock shafts I'd take the steel.

[allbaugh_04]

Anyone happen to know about carbon fiber drive shafts? I know they are probably retarded expensive, but i was just curious how much hp you could save,that's a lot of weight saved and rotational mass...

[Firebirdjones]

Anyone happen to know about carbon fiber drive shafts? I know they are probably retarded expensive, but i was just curious how much hp you could save,that's a lot of weight saved and rotational mass...

Ya they are a tad lighter than chrome molly. I just don't care for it though. Guess they can be made strong but I have a hard time with it.

Chrome molly is the lightest (metal) shaft and the strongest, even lighter than the aluminum shafts. It's the way to go in my opinion.

[allbaugh_04]

IC, good info. thanks