Gm 12 bolt vs. Ford 9"

[Cart]

In your opinion what is a better rear differential. Taking into account not just performance, but things like durability, how easy they are to work on, and cost.

[anotheridiot]

easy to work on would go to the ford 9". 8 bolts, slide out the axles, pull the pumpkin and take it inside the house. a simple jig with angle iron can be welded together, drill a couple holes and you lock it in a vice.

[JeffMcKC]

What car is it going in?

12 bolt Plus
less rolling resistance


9 inch Plus
More gear choices
Easy set up
Borrow a gear easy
Stronger Gear
Stronger housing

[MR P-BODY]

Well you have good and bad on both units... a 12 bolt uses less power
to run it BUT its not a pig unit so you have to work on it in the car...
the 9" is a pig and you can pull it easy... it does take more power to
run it and in reality it needs to have the fancy parts to have them live
if you have any power..... I went with a 9" in my Rampage but its a
light car and I put SOME of the fancy parts in it.... it seems like there
are parts everywhere for the 9" so your chances of getting parts for
it would be easier...... JMO

[TheSilverBuick]

I'm in the same boat. After eating an axle last year in my 8.5" 10-bolt I'm looking to do a full rear end swap to get rid of the c-clips at the same time. If I go with a 9" 3.55 gears then my speedo and odometer would be spot on.

[anotheridiot]

.......and I am usually an all chevy guy too. If I didnt get a ford 8" in the 36 already shortened I would probably not have chosen one, but we ran a ford 9" in our FED injected nitro small block chevy and never had one single issue running 7.70@189.

[squirrel]

Get a 9" center that uses 12 bolt gears, if you're worried about the power loss. You still have several of the other advantages of the 9" that way. And it's lighter than the 9" center.

I have a normal 9" and I kind of like having a whole selection of 9" gears ranging from 2.47 to 4.11 that I didn't pay more than an average of $40/set.

[SuperBuickGuy]

Street Rodder magazine did a comparison of the Olds rear vs. the 9 and 12 - wow, seems that choice would be cake and eat it too


except, of course, for the ability to borrow from others....

[MR P-BODY]

I build a nostalgia altered for my brother and went with the Olds rear end
which back in the day was suppose to be the strongest with the least power
to run it

[squirrel]

The olds is a neat rear, too bad it's kind of scarce these days. The 9" has so many parts available....

[TC]

I think the biggest plus to a 9" is the pinion support on the front of the pinion gear, which is something the 12 bolt doesn't have.....

[A/Fuel]

If you go with the 9" because it's easier to work on you'll need an extra 3rd member and gears to make it worth while. When we used the 9" rears I used to be able to change it in about 30 minutes, and I did it a couple times a month. Thats having all the tools ready.
As far as borrowing one, I don't know the way you guys do it but, I would just ask that you replace it when you get a chance. We could only get 30 runs or so out of a ring & pinion before the pinion gear would crack, or if the tires shook it would be a lot less.
I was pretty glad when we switched to the 10.5 strange rear.

[JeffMcKC]

After a certain ET C-Clip eliminaters get used.
Axels slide right out.

http://www.jegs.com/p/Strange-Engineering/Strange-C-Clip-Eliminator-Kits/744492/10002/-1

8.8 rear ends would be a better choice, with Eliminators on it.

I ask what car because a 12 bolt in a G-Body puts the ears on top in a bad position, and its a Hook Nightmare!!!!

[quick 52]

had a new gear in a couple days before drag week a 9" 3.89.. day 3 that gear got so loud that i didnt think it would make the rest of the trip.. called the shop he said cant hurt it now just run it so i did. when the week was over the shop replaced the gear 2 weeks later it to was getting loud in all it was replaced 3 times been good for 3 year's now

[JeffMcKC]

I buy used Nascar gears from Ebay...............