1BadBrd

If you had to choose and the strength was the factor, which would you go with.

The extra weight and extra HP lose is a small factor but i do not want to put in a 12 bolt and purchase some slicks and brake a 12 bolt. I have stock bottom end now but will be getting the 383 in the near future so.....

IDOXLR8

I would think for your setup you can get by with a Moser 12 bolt. They are advantages to both rearends. Both are capable of breaking if your suspension is not setup properly.

Injuneer

The 12-bolt holds up well to about the 800HP level. I've seen them run closer to 1,000HP. There appears to be a lot of stories going around of LS1's breaking 12-bolts... not sure why. I've never seen one break.

Things to think about in addition to the HP loss and the wieght issue:

-driveshaft length
-TA mounting issues (offset from stock)
-u-joint stress (lower pinion height)
-tunnel clearance
-sway bar mount
-ABS availablity

You might want to do a "search" on the "Drivetrain" forum, which is where Brent is probably going to move this thread to.

WS Sick

Inguneer , are you saying these are the downsides to the 9 inch?
does the 12 inch use the factory length prop shaft?

Injuneer

I'm just saying you need to think about these things, and determine how they relate to your specific application.

The 9-inch does lose 3% more power.

The (standard iron) 9-inch is heavier.

The 9-inch drops the pinion centerline 3/4", increasing stress on the u-joints and making pinion angle more critical

The 9-inch offsets the TA mount slightly to the drivers side, requiring a different set of holes on the TA to avoid putting it in bind.

The offset of the TA and the size of the housing can require some tunnel pounding when you install a 9-inch.

About 50% of the people need a shorter DS with the Moser 12-bolt. I ***think*** the 9-inch requires a different length than either the stocker or the Moser 12-bolt.

I don't know about the availability of 3-channel ABS with the 9-inch... and it may be possible to cobble up some sort of an interface between a car with a 3-channel system and a 9-inch with a 4-channel option. I honestly do not know. Just poihnting out that is it a "consideration".

The sway bar mount is a problem with the Moser 12-bolt... you need the Spohn bracket kit, or some other solution. I would suspect the 9-inch is similar since the axle tubes are larger than a stock 10-bolt.

My personal preference is the Strange 12-bolt, but he didn't ask about that one.... It uses the factory DS length, comes fully assembled, has the same axle tube diameter as stock, has the same TA mount setup as stock... etc.

I also don't think that DS length should be a biggie.... if you are making enough power to justify the expense of one of these rear axle assemblies, an new DS might be a good idea. I saw a Lingenfelter 3.5" aluminum shaft break at about the 750HP level.

INTMD8

I've got a KTRE 12 bolt and I've broke 2 ring and pinion sets, and a differential.

(Maybe the Strange/Moser are stronger)

I would like to make the switch to a 9in, but as Injuneer mentioned, it takes some 'massaging' of the floorboards, and there isn't a good solution for 3 channel abs.

WS Sick

That sounds bolt in enought to justify it. I beleive from this alone I would do the strange (that sounds wierd)

1BadBrd

after talking with many people and suppliers i think i will go Moser 12 bolt. Although the 9" is what i was looking for as far as strength, i think the 12 bolt will last upto 750 hp and far as extra money to make the 9" fit will put me over what i really want to spend.