OK, i basically know nothing about rear axles, differentials, third members, housings.... etc
so i sorta need to cut through the bullsnot, and get a straight forward answer to a couple things...
Whats it take to use a 9" rear in a 67 mustang?
What Vehicle can i find with a 9" Posi?
and Besides the obvious benefits of a posi,is a 9" worth the swap?

 

oh and whats better a posi, or lsd?

 

Read this on the posi/lsd/detroit/spool...

http://en.wikipedia.org/wiki/Limited_slip_differential

You will need a housing and center section to put the 9" in your car (the axles you can use from the 8" if you want to stay with a 28 spline). You really don't need a 9" unless you pan on making some horsepower. You can get a posi for the 8" diff as well. Is the rear end that you have messed up (as in broken)? Do you drag race or do some sort of racing? Do you have some traction issues?

 

no issues, acutally, but thats partly because ive never driven the car more than 5 feet
LOL

anyway i'm not trying to drag race, i just want something dependable, and avoid the "one tire frier" didn't know they had 8" posi's it thought it might be in my best interest to find a used one from a junkyard.... so i figured if i'm pulling one it might aswel be a 9

 

Positraction is a GM trade name for a type of limited slip differential (LSD). LSD and locking differentials include trutrac, traction lock, Detroit locker, etc. You don't really need a 9" unless you are running north of 350 ft/lbs of torque. Your best approach may be to upgrade your existing 8" rear to a traction lock.

 

http://www.ultrastang.com/Page.asp?PageID=6
http://www.kevinstang.com/Ninecase.htm
http://dazed.home.bresnan.net/narrowinga9.html

You can try to find a center section from a mustang II, they usually had 8" rears with 3.25 gears and traction lock. If you want 9", start reading from the links i gave you. Sorry if they don't work.

 

ok, im sure you have realized by now im a broke high school student and just wanted to find a LSD or something in a junkyard somewhere... and thought a 9" would be more readily available, like i said i am completely un knowledgeable on the subject

 

thnaks snorulz, thats what i needed

 

you have most likely seen some of my 9" posts lately. I am shortening a 9" from a 68 f-100 with 3.5 gears and 4 pinion Traction Lock. If you have any questions pm me, i will answer them if i can.

 

Something like this if you want something more suited for the street...

http://www.jegs.com/i/Detroit+Locker...2A580/10002/-1

http://store.summitracing.com/partde...5&autoview=sku

or something like this if you want a locker, more suited for street/drag racing....

http://www.jegs.com/i/Detroit+Locker...7S13D/10002/-1