So, what are the pros and cons? I'm leaning 12 bolt just because I'd rather not have a Ford part on my car, but how about some insightful comparisons. Any links to comparisons? Thanks.

Larry

 

The 9 inch is the ultimate rear end. The center sections can be swapped out instead of taking the whole rear out.


Do a search this ? has been asked many times.

 

If you want to keep your ABS then I would recommend going with a 12-bolt. 12 bolts are very strong and there are a few people on this board that are running big hp through these rearends without any problems. Once you start getting to the 800 hp then I would recommend going with a 9-in. I currently have a Moser 9-in and it was a PITA to get the center section in. I was working on a lift also so I could just imagine how hard it would be to do the install on your back. Another disadvantage of a 9-in is that they are heavy and require more power to turn them. Personally I believe for an everyday car a 12-bolt is more pratical. If you are looking for an all out drag car then I would go with a 9-in.

 

A few thoughts:

-9-inch is heavier

-9-inch loses 3% more power

-9-inch has a lower centerline for the pinion shaft (one of the causes of mechanical power loss) which increases the offset in the driveshaft, wear on u-joints.

-9-inch has the torque arm mount offset to drivers side, requiring a TA spefically for the 9-inch. Spohn has these, for example... just different mounting hole locations in the rear mount.

-clearance in tunnel gets tight on 9-inch.

-9-inch has "quick change" center section, allowing multiple carriers and ratios for swapout at the track. The TA mount does complicate removing the center section a bit.

-9-inch has the ability to be a much stronger rear. But that's only if you buy it with "much stronger" parts... heavier axles, more bolts in the pinion support, etc. In a base configuration, the 9-inch and 12-bolt will be similar in strength.

-My experience says a 12-bolt is fine for 800HP, but thats an automatic. With an M6 and 6K clutch dumps, you might want the 9-inch at that level. I saw a Strange 12-bolt take 950flywheelHP, with a TH400.

-I thought Moser was now selling an ABS option on the 9-inch, but that might only be a 4-channel option...

-9-inch has a huge selection of gear ratios... and some that fit nicely between the typical 12-bolt 3.42, 3.73, 4.10, 4.56 ratios.

I think that up to 800HP, with an automatic, the 12-bolt would be a wise choice. Above that, go with the 9-inch. For an M6, that changeover point is probably a little lower. Depends how you use it.

 

My experiences are that a 12bolt built with the right parts will be strong enough to get you in the 8's with an automatic. If you plan on making more power than that go with a 9inch. My dads 4400lb Impala with driver has run 9.60's @140+mph with a 12bolt Everybody said it wouldn't hold but it has been in the car for about 10yrs with many many abusive transbrake launches. It has been a unbeleivable 1.17 60' only once but it did do it. The car usaully 60's 1.3's though. The axle tubes are welded up and it has Moser axles with a spool and all the good stuff. One thing that probably helps is the car always spins thru the 60' with 1200hp. except for the one time iot hooked up and ran that 1.17 60' and it's still kickin. We pulled the axles last year and they were very slightly twisted from the carrier all the way to the flange so we replaced them but they were 8yrs. old
Either is a good choice but I prefer the 12bolt for most street/strip cars. Whenever I break my 10bolt that runs 1.5 60's I will go that route. Later Goodluck

 

The Strange 12 bolt even comes filled with fluid....completely assembled....all that is needed is paint.

Joe

 

Not really important but my uncle who did a lot of track/strip back in his day kept breaking axles and his buddy (a Ford guy) convienced him to put in a 9 inch. Last run of the night the axle grenads itself. Next day my uncle was telling the ford guy what happened that chevy had to be so much better b/c the only ford part on the car breaks. Guy smiles and said that it just woke up and realized it was under a chevy and killed itself!

 

Ultimate strenght is the DANA 60 not Ford 9 inch. Just get a 12 bolt with good intenerals and Ford ends, so you don't have to mess with the c-clips. That way is is as strong as a Ford 9 in most cases and you still get the better efficecy(sp) of the 12 bolt. But if you are looking for the ultimate strengh a DANA 60 is had to beat ( but they are big and heavy).

 

Out of the 12 bolts which do you think is better. The moser or the strange? And why?

 

the one with better components.

 

Weren't people having problems with the factory Moser gear installs? Problems like excessive gear whine and breakage....they did pay for a local shop to do a gear install if I remember correctly however. Also I think you are more likely to need a new driveshaft with a Moser....haven't heard of someone with a Strange needing one yet. They are both .... overall ... good rears IMO....and I haven't heard of Moser problems recently that I recall.

Joe

 

Actually, I like the Nationwide Performance Driveline 12 bolt setup. They use a KTRE nodular housing, Eaton posi, Moser axles, US Gear gears, Timken bearings with roller bearings out on the axle ends, and the axles are semi floating so there's no c-clips. $2050 Add $100 if ya want to keep the abs. As good a deal for one as tbyrne has on a group purchase.

I'm definitely going 12 bolt. Either going with the Nationwide one, or picking up the KTRE housing and putting it together myself, if I can save a few hundred. Do ya think it would be worth doing it myself? I know I'd have to pay someone to have the bearings pressed on, and I'd probably need someone to set up the ring and pinion right. Any "how to"s out there with some good step by steps for assembly?

Thanks for all the replies so far.

Larry