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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Rearend help...

  • Thread starter Thread starter XStang302x
  • Start date Start date Jul 21, 2004

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Jul 21, 2004
#1
  • Jul 21, 2004
  • #1
Rearend ID?

Hell...gonna take it apart this weekend and pray it doesnt rain till then heh.

Anyways, trying to figure out if I have a 8 or 9 inch rear.

68 coupe that originally came with a 289. There is no back cover plate on the rearend. It's a solid piece with a removable center from the front. I can't seem to find any guides to help decode the ID # = C70W 4025A 29. According to my shop manual from the VIN plate decoder it's a 2.79 with an 8" , who knows what PO's might have put in. I could get a socket around the bottom 2 bolts (which I was told indicates 8", was a tight fit though), maybe I have funky sockets? I have a buddy telling me it's definitly a 9" . I found a website that explained how to designate between the two, and they had a 9" with an ID number of C7AW 4025A ?? (can't remember the last two, if that even matters). Mine being only 1 letter off is what has me confused, assuming it's probably just a year indicator. Plus, I've heard that it being a solid back piece with the removable front indicates it being a 9".

Any advice from anyone with experience would GREATLY be appreciated. Looking to yank this puppy off over the weekend, hopefully go ahead and preorder any parts I need and get em on the way and have it back in early next week.

-Frank
 

68GEETEE

5 Year Member
Nov 21, 2003
481
5
38
Texas, USA
Jul 21, 2004
#2
  • Jul 21, 2004
  • #2
I cant remember about the socket test, but someone here will know.
 
R

Ronstang

New Member
Apr 4, 2004
1,294
0
0
Houston Texas
Jul 21, 2004
#3
  • Jul 21, 2004
  • #3
If you can get the the botton two bolts with a socket going straight on then it is definitely an 8", you cannot get a socket on them on a 9".
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Jul 21, 2004
#4
  • Jul 21, 2004
  • #4
Hmm...lookin' like an 8" then.

Are parts for these readily available? Or is this gonna have to be some special order deal from the mustang shop?

-Frank
 
R

Ronstang

New Member
Apr 4, 2004
1,294
0
0
Houston Texas
Jul 21, 2004
#5
  • Jul 21, 2004
  • #5
Stuff for these rearends is easily obtainabe at the auto parts store and gears sets can be had from any place you would get them for a 9".

What exactly are you planning on doing to the rearend?
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Jul 21, 2004
#6
  • Jul 21, 2004
  • #6
Haven't taken it apart yet, but have a horrid noise on decel. So I'm assuming something is about to break. Going to try and yank it out tomorrow night and see what's up. I'm planning for the worse and just making sure fixing it will require little down time. Just not having any luck finding 8" parts on sites like summit and what not. I'm probably just being mentally retarded in that area. I see 9", 8.8" and 7.5" all over the place though.

-Frank
 

XStang302x

Founding Member
Nov 2, 2000
286
24
19
Marietta, GA
Jul 22, 2004
#7
  • Jul 22, 2004
  • #7
Sorry to be the post whore of the night...

I'm on a limited budget...I would like to get this fixed for under $500. I have a buddy who can help me get everything measured and assembled, so parts cost is the main worry.

With the curent mods (not much) it's pushing 300ft/lbs of torque and 190hp at the wheel. Is the 8" suitable for that amount of torque? If not I wouldnt mind spending a lil more for the 9" just to prevent future problems.

I don't know anything about rearends, though I'm learning very quickly lol.

Any opinions?

-Frank
 
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