Moser 9 inch vs. Moser 12 bolt
09-02-2011, 10:38 PM
#1
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Moser 9 inch vs. Moser 12 bolt Whats the main differences? What are the better suited uses for each? I will be purchasing one of these very soon and would like some of your opinions
09-02-2011, 11:14 PM
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im not expert but, from what i've seen/read, 12 bolts are lighter than 9", the internals in the the 9" are bigger making it stronger, also the 12 bolt tend to become noisy after a couple of hard launches due to deflection, also you'll experience more hp loss from a 9" than a 12 bolt, so you'll have to decide which way you wanna go, both are great rears, some will say if you're making over 500 rwhp go with a 9" and 12 bolt under 500 rwhp. Hopefully someone more experience would chime in and explain it better, also i think Bob has a great write up about the differences on each rear end. I personally would go with a 9" same price as the 12 bolt and you get a bullet proof rear.
check this link, is from Bobs page, very informative.
http://shop.brutespeed.com/Brute-Spe...nformation.htm
check this link, is from Bobs page, very informative.
http://shop.brutespeed.com/Brute-Spe...nformation.htm
09-04-2011, 03:51 PM
#4
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09-05-2011, 02:33 PM
#7
Copied from Bob @ Brutespeed
10 Bolt, 12 Bolt and 9 inch Information
The factory 10 bolt that came in these cars has a very small 7.5" gear. A variation of this rear was used back in the '70's in the Chevy Monza, then in the Chevy S-10. GM had to of known they would have warranty claims when they decided to use this rear in the 3rd and 4th gen f body's, apparently the cost of creating a stronger rear was higher than what they thought the warranty cost would be. This has been a real plus for the aftermarket, as a bone stock LS1 F Body with a manual transmission can break one of these 10 bolt rears! Many people have tried to beef these 10 bolt rears, spending a lot of money in the process. What they normally end up with is a rear that still breaks, as everything on these rears is too small.
The 12 bolt rears that are available for these cars is a step in the right direction. The 12 bolts are well known for being a stout rear that was a factory option back in the day in many performance cars. You can have a 12 bolt in an early Chevelle, Nova, Camaro, etc, and beat the snot out of it and not hurt anything. Put a 12 bolt into a late model f body that uses a torque arm, make a couple 4000 to 5000 rpm launches at the dragstrip, and I can just about guarantee you'll have a lot more gear noise on the way home. The torque arm seems to distort the housing on the 12 bolts, and it seems to happen to all the brands of 12 bolt rears. This does not happen to the 9 inch rears, and there is no price difference between the 12 bolt and nine inch rears. As the horsepower in our engines keep escalating, most people these days go straight to the nine inch rear. The 9-inch has an internal rear-pinion support that also supports the gear end of the pinion to limit gear deflection under high torque loads. This seems to be the major reason why the 9 inch doesn't start whining after high rpm clutch dumps, when the 12 bolt will pick up noise. The 9-inch locates its pinion gear lower on the ring gear to improve tooth contact, better the 12 bolt does. The 9-inch also has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt
It's a 1350 conversion u-joint. You can get it from napa.
If your goin with an M6 swap get a 9". Do it right the first time. I've pounded on mine relentlessly and it doesn't flinch. The 9" inch on avg takes away 13hp, but leaving at 5500-6500+ as opposed to 1500-3000 makes up for it. You can also build the center strong and cheap if you buy and shop smart. I bought a used moser aluminum center for $680 with a spool and gears then waited til a gear/install kit sale came and bought. Had a local shop set it up and buy the time it was done I had maybe $900 in the center and $1100 in the moser axle package. You may say I only saved $300 on the initial cost but a PST shaft was $400 at the time so I almost saved enough to cover the full cost of the DS. Reading the classifieds work out sometimes, but you gotta be quick lol.
10 Bolt, 12 Bolt and 9 inch Information
The factory 10 bolt that came in these cars has a very small 7.5" gear. A variation of this rear was used back in the '70's in the Chevy Monza, then in the Chevy S-10. GM had to of known they would have warranty claims when they decided to use this rear in the 3rd and 4th gen f body's, apparently the cost of creating a stronger rear was higher than what they thought the warranty cost would be. This has been a real plus for the aftermarket, as a bone stock LS1 F Body with a manual transmission can break one of these 10 bolt rears! Many people have tried to beef these 10 bolt rears, spending a lot of money in the process. What they normally end up with is a rear that still breaks, as everything on these rears is too small.
The 12 bolt rears that are available for these cars is a step in the right direction. The 12 bolts are well known for being a stout rear that was a factory option back in the day in many performance cars. You can have a 12 bolt in an early Chevelle, Nova, Camaro, etc, and beat the snot out of it and not hurt anything. Put a 12 bolt into a late model f body that uses a torque arm, make a couple 4000 to 5000 rpm launches at the dragstrip, and I can just about guarantee you'll have a lot more gear noise on the way home. The torque arm seems to distort the housing on the 12 bolts, and it seems to happen to all the brands of 12 bolt rears. This does not happen to the 9 inch rears, and there is no price difference between the 12 bolt and nine inch rears. As the horsepower in our engines keep escalating, most people these days go straight to the nine inch rear. The 9-inch has an internal rear-pinion support that also supports the gear end of the pinion to limit gear deflection under high torque loads. This seems to be the major reason why the 9 inch doesn't start whining after high rpm clutch dumps, when the 12 bolt will pick up noise. The 9-inch locates its pinion gear lower on the ring gear to improve tooth contact, better the 12 bolt does. The 9-inch also has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt
If your goin with an M6 swap get a 9". Do it right the first time. I've pounded on mine relentlessly and it doesn't flinch. The 9" inch on avg takes away 13hp, but leaving at 5500-6500+ as opposed to 1500-3000 makes up for it. You can also build the center strong and cheap if you buy and shop smart. I bought a used moser aluminum center for $680 with a spool and gears then waited til a gear/install kit sale came and bought. Had a local shop set it up and buy the time it was done I had maybe $900 in the center and $1100 in the moser axle package. You may say I only saved $300 on the initial cost but a PST shaft was $400 at the time so I almost saved enough to cover the full cost of the DS. Reading the classifieds work out sometimes, but you gotta be quick lol.
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09-05-2011, 07:40 PM
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Not all 9"s take the 1350 u-joint, only Mosers or other aftermarket yokes. I'm building a stock Ford center section into a Moser 9" housing and it uses the same u-joint as stock.
09-05-2011, 09:46 PM
#9
BTW, a stock ford center (unless you're buying a ford racing center) will not support a full weight cam only car for long. It can't take the force generated by the M6 and almost always cracks the housing where the pinion bearing is. It may not be right at first, but it will happen. Seen my buddy and a few other guys go through them. It'll be fine on the street, but if you plan on racing it and launching hard, I'd save for atleast a nodular for when the stocker pops.
09-05-2011, 09:47 PM
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Get a 9 inch like they said. I'm just glad it came in the car already instead of paying all the money for a rear end to have it make a bunch of noise. My 12 bolt is noisy but I can live with it.
09-06-2011, 02:47 AM
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Well considering this thread is about MOSER REARENDS which take the 1350 then I'm pretty sure that's the info he was looking for.
BTW, a stock ford center (unless you're buying a ford racing center) will not support a full weight cam only car for long. It can't take the force generated by the M6 and almost always cracks the housing where the pinion bearing is. It may not be right at first, but it will happen. Seen my buddy and a few other guys go through them. It'll be fine on the street, but if you plan on racing it and launching hard, I'd save for atleast a nodular for when the stocker pops.
BTW, a stock ford center (unless you're buying a ford racing center) will not support a full weight cam only car for long. It can't take the force generated by the M6 and almost always cracks the housing where the pinion bearing is. It may not be right at first, but it will happen. Seen my buddy and a few other guys go through them. It'll be fine on the street, but if you plan on racing it and launching hard, I'd save for atleast a nodular for when the stocker pops.
And yes, I have done plenty of research on the stock Ford cases. This car might see the drag strip once a year, twice if I'm lucky. It's a street car. If/when it breaks, I'll get a lightweight nodular or bolt-thru aluminum and a billet 1350 yoke.
09-06-2011, 08:57 PM
#12
not hijacking a thread, but i had a long talk with Jason at texas drivetrain (AKA diamond clutches)........very reputable man,and he completely talked me out a moser 12 bolt.......and got mehooked on a strange 12 bolt instead.......he said he has taken apart every rear available for the fbody,and he said the strange is a mch higher quality.........plus they are actually designed for a torque arm, unlike the moser........he said the insides are identical to the S60, but not quiiiiiiiiite as beefy as the 1000rwhp rated s60, he said the best part is no rear end whine........ever........haha and its even usually cheaper than the moser.......the strange 12 bolt is a hassle free installation, and i heard some people had some minor fitment issues with the mosers.....hope this helps
Last edited by Floorman279; 09-06-2011 at 08:59 PM. Reason: .........
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09-07-2011, 12:45 PM
#18
not hijacking a thread, but i had a long talk with Jason at texas drivetrain (AKA diamond clutches)........very reputable man,and he completely talked me out a moser 12 bolt.......and got mehooked on a strange 12 bolt instead.......he said he has taken apart every rear available for the fbody,and he said the strange is a mch higher quality.........plus they are actually designed for a torque arm, unlike the moser........he said the insides are identical to the S60, but not quiiiiiiiiite as beefy as the 1000rwhp rated s60, he said the best part is no rear end whine........ever........haha and its even usually cheaper than the moser.......the strange 12 bolt is a hassle free installation, and i heard some people had some minor fitment issues with the mosers.....hope this helps
Your an auto according to your sig. If you've never launched a M6 all out you have no idea of the damage and destruction they can cause. These transmissions with a good race style clutch getting turned loose at 6000+ rpms will beat a 12 bolt down. In some instances (on this board even) I've seen them break behind an M6. The OP wants to swap to an M6 so whether it's moser, strange, or who ever, he needs atleast a 9" if he's wanting to beat on the car at the track with sticky tires. Less worry IMO.
09-07-2011, 01:01 PM
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Ok so i am probably going with the 9" but now i need to decide between a spool with only 300 miles on it or a posi with 10k on it....i know the spool is not as street friendly but i know some people still drive it daily on the street. I do not want to ever buy another rear end so should i tough it out and go with the spool or just stick to the posi and take my chances?
09-07-2011, 07:20 PM
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Ok so i am probably going with the 9" but now i need to decide between a spool with only 300 miles on it or a posi with 10k on it....i know the spool is not as street friendly but i know some people still drive it daily on the street. I do not want to ever buy another rear end so should i tough it out and go with the spool or just stick to the posi and take my chances?