12 bolt vs. 9 inch Ford Rear end.

mcutlass1969 · January 25th, 2008, 02:56 PM

Looking to beef up the rearend. It is now the weekest link in my drivetrain. In talking to guys I have heard of 12 bolt GMs but also had heard Ford 9 inch rearends are the best way to go? So what are the PRO's and CON's? I would like to know the workout up front in going to a Ford 9 inch.

marcar1993 · January 26th, 2008, 09:28 PM

It depends, what car is it going into. The 9" is stronger, but not a bolt in and expensive. A 12 bolt can be built pretty strong, and is a direct bolt in (some of them) into a-body cars. Any a-body 12 bolt also can be bolted into a g-body with adapter control arms from umi.

The_Jeremiah · January 27th, 2008, 01:20 AM

if your going to be changing the gear ratio at all in the future, your better off going with the 9" because you wont have to do as much shimming and what not. If your just looking to replace the rearend, definently go with a 12 bolt. its just like the 10 bolt, but stronger, like marcar said it will bolt right in

mcutlass1969 · January 28th, 2008, 07:47 AM

Thanks guys. Here is a little more info. I am putting this in a 69 Cutlass S. I pulled the 350 out and put in a 455/TH-400 combo. I have been pretty gentle on the car but would like to take it to the local track to see what it will do. Right now I am running the factory rearend and it is starting to leak and figure it would be a good time to put in another rearend.

January 28th, 2008, 09:02 AM

in all actuality a 10 bolt can be built up almost as strong as a 12 bolt...there isn't too much difference between the two.

my 455/t-400 is getting a super beefed up 10 bolt, and i'm having my driveline guy do the work.

Goose · March 6th, 2008, 11:24 AM

I put in a Moser 9" August 2006 under my '68 Supreme and love it. Full spool, 4.33 gears, 35 spline axles, drum - drum for around $2200 to my door. Added about 60 pounds over the 8.5" 10 bolt 3.90 that I swapped out and put under the wife's '68, but it's strong rnough to take anythig I'll through at it.

Oh, and it was a direct bolt-in, NO issues!

January 25th, 2008, 02:56 PM	#1 (permalink)
mcutlass1969 Registered User Join Date: Apr 2006 Posts: 75	12 bolt vs. 9 inch Ford Rear end. Looking to beef up the rearend. It is now the weekest link in my drivetrain. In talking to guys I have heard of 12 bolt GMs but also had heard Ford 9 inch rearends are the best way to go? So what are the PRO's and CON's? I would like to know the workout up front in going to a Ford 9 inch.

January 27th, 2008, 01:20 AM	#3 (permalink)
The_Jeremiah Registered User Join Date: Jul 2007 Posts: 294	if your going to be changing the gear ratio at all in the future, your better off going with the 9" because you wont have to do as much shimming and what not. If your just looking to replace the rearend, definently go with a 12 bolt. its just like the 10 bolt, but stronger, like marcar said it will bolt right in __________________ 69' Cutlass 4 door. Built 455 inside, grandma's grocery getter outside. Best sleeper in disguise.

March 6th, 2008, 11:24 AM	#6 (permalink)
Goose Junior Member Join Date: Aug 2002 Location: Washington Posts: 4	I put in a Moser 9" August 2006 under my '68 Supreme and love it. Full spool, 4.33 gears, 35 spline axles, drum - drum for around $2200 to my door. Added about 60 pounds over the 8.5" 10 bolt 3.90 that I swapped out and put under the wife's '68, but it's strong rnough to take anythig I'll through at it. Oh, and it was a direct bolt-in, NO issues! __________________ If you're not havin' fun, you're doin' somethin' wrong. Last edited by Goose; March 6th, 2008 at 11:27 AM..

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
1968 442 3.90 posi 12 bolt olds rear for sale	monzaz	Parts Wanted	1	September 16th, 2009 09:22 AM
(68-70) 12 Bolt "O" axle rear end	dan1s	Parts For Sale	4	September 23rd, 2008 02:53 PM
68 Type O 12 Bolt Rear End	Topless72	Parts For Sale	5	January 18th, 2008 08:11 PM
rear-end help.	Joel n	Eighty-Eight	3	December 3rd, 2006 10:48 AM

January 26th, 2008, 09:28 PM	#2 (permalink)
marcar1993 Registered User Join Date: Apr 2007 Location: CNJ Posts: 163	It depends, what car is it going into. The 9" is stronger, but not a bolt in and expensive. A 12 bolt can be built pretty strong, and is a direct bolt in (some of them) into a-body cars. Any a-body 12 bolt also can be bolted into a g-body with adapter control arms from umi.

January 28th, 2008, 07:47 AM	#4 (permalink)
mcutlass1969 Registered User Join Date: Apr 2006 Posts: 75	Thanks guys. Here is a little more info. I am putting this in a 69 Cutlass S. I pulled the 350 out and put in a 455/TH-400 combo. I have been pretty gentle on the car but would like to take it to the local track to see what it will do. Right now I am running the factory rearend and it is starting to leak and figure it would be a good time to put in another rearend.

January 28th, 2008, 09:02 AM	#5 (permalink)
dar83501 Guest Posts: n/a	in all actuality a 10 bolt can be built up almost as strong as a 12 bolt...there isn't too much difference between the two. my 455/t-400 is getting a super beefed up 10 bolt, and i'm having my driveline guy do the work.