GM 12 bolt or Ford 9 inch

[Qdub24]

I'm replacing my 7.5 rear in the spring. I need help picking a rear assembly from Moser. I'm definitely running 30+ spline axles, posi or a locker, and 3.73-4.11 gear ratio. I may also add disc brakes to the axle package. Also, are either of these c-clip axles?

 

[nycutlass]

I'm replacing my 7.5 rear in the spring. I need help picking a rear assembly from Moser. I'm definitely running 30+ spline axles, posi or a locker, and 3.73-4.11 gear ratio. I may also add disc brakes to the axle package. Also, are either of these c-clip axles?

well i could use some more info on the car and what it will be used more for .....but i will say if your going to use it hard and have lots of hp i would go with a ford 9 inch .they are proven on the track for years to last i think its the best bang for your buck.i know i can build a custom ford 9 with disk brakes for less than a 12 bolt rear ....i am running a ford nine in my car with rear disks with np.but on the other hand the gm 12 bolt can hold its own too but will cost you in the long run by the time your done with it ,its also alittle wider but could help you on the track with wider tires ,i have seen some people cut off the stock flang and weld in ford nine flanges ,i just like the idea of taking 40 min and swaping gears out with my ford 9 just by removing a few bolts.its a plus for a 3 speed transmission car set one up for cruzin and one up for the track .

 

[MD13ailey]

I'm fairly sure the 12 bolt does have C clips and the 9 inch does not

 

[Qdub24]

well i could use some more info on the car and what it will be used more for .....but i will say if your going to use it hard and have lots of hp i would go with a ford 9 inch .they are proven on the track for years to last i think its the best bang for your buck.i know i can build a custom ford 9 with disk brakes for less than a 12 bolt rear ....i am running a ford nine in my car with rear disks with np.but on the other hand the gm 12 bolt can hold its own too but will cost you in the long run by the time your done with it ,its also alittle wider but could help you on the track with wider tires ,i have seen some people cut off the stock flang and weld in ford nine flanges ,i just like the idea of taking 40 min and swaping gears out with my ford 9 just by removing a few bolts.its a plus for a 3 speed transmission car set one up for cruzin and one up for the track .

The car it's going in is an 83 Cutlass w/a freshly built Buick 455 and TH350 w/B&M Megashifter. I'm continuously upgrading the motor and trans. A new cam, aluminum heads, stall, and new intake are also in the works. The car will see more street time than track time, but it'll probably be at every test & tune night.

 

[nycutlass]

you might want to do the ford 9 then you change the gears when u do test and tune night . you have that 3 speed transmission so make one 3rd member 3.00 or 3.25 trac loc for around town and set up the other 3rd member with 4.11 or 5.13 spool for tune night

a stock ford nine with a rebuild can hold around 650-700 hp

 

[Qdub24]

you might want to do the ford 9 then you change the gears when u do test and tune night . you have that 3 speed transmission so make one 3rd member 3.00 or 3.25 trac loc for around town and set up the other 3rd member with 4.11 or 5.13 spool for tune night

a stock ford nine with a rebuild can hold around 650-700 hp

alright, thanks

 

[nycutlass]

np at all .like i said its one way to go .i can post a few pictures if you like

 

[86Cutlass383SR]

I've talked to Moser on the phone about their 12 bolt. You can have them install a Ford type housing end that eliminates the c-clips but it has the same bolt pattern as the GM 10/12 bolt brakes. Advantage: same Ford type axle retension but you can still use any GM style brakes.

I do like the quick gear ratio change possibilities of the 9" but that also means the added cost of a second third member. In my case, I really doubt I'll be doing any gear changing.

9" has more parts to buy unless you buy a complete housing assembly. Total costs seem about the same overall.

If weight and/or power-to-the-wheels is of any concern in your case, that would be another thing to look at. I'm not sure which one is lighter but I've read that one takes more hp to turn than the other which would eat up some of your rear wheel hp. Moser will know for sure which one but it's another thing to look at.

I couldn't vote as I'm still uncertain which I'll end up buying. Probably the 12 bolt so I can stay all GM. But that's just personal preferance.

 

[Minion1186]

i picked the ford 9 inch,i'll be getting one once i have enough,i think the best combo for you would be a posi,4.11 gears and 30 spline.

 

[nycutlass]

i picked the ford 9 inch,i'll be getting one once i have enough,i think the best combo for you would be a posi,4.11 gears and 30 spline.

there was no 30 spline it was 31 spline