CaliforniaSpecial.com -- Message Boards -- 1968 California Special Limited Edition Ford Mustang GT/CS
D I S C U S S I O N . F O R U M
COMMUNITY
1968 GT/CS & HCS
2007+ GT/CS
1966-1967 HCS

Vote!

Old 06/02/2007, 07:20 AM   #1
Mosesatm
 
Mosesatm's Avatar
 

Location: Spokane, Washington
Joined: Jan 05
Posts: 7,351

28 spline vs 31 spline Rears

Are all 2.79 rears 28 spline units?

Which units have 31 splines?
Mosesatm is offline   Reply With Quote
Old 06/02/2007, 12:25 PM   #2
robert campbell
My Car Details
 

Location: Bremerton Washington
Joined: Apr 07
Posts: 3,646

My Garage
Arlie,
To my experince The rear end in you car should be an 8 inch vice a 9 inch. 390 or 428 cars mostly have 9 inch rear ends. Some "J" code cars may have a lower (3.50 to 4.11 ratio) which may be a nine inch a posi and have 31 splin axls. All in how the buyer checked the option sheet. Any thing could happen.

To my knowledge all 2.79 rear ends of the 8 inch variety are 28 spline. Many 9 inch open rear ends and some posi 9 inch are also 28 spline. The lower ration 9 inch, 4 pinion, traction lock (posi) rear ends mostly or all have 31 spline axels. Hope this helps.

Rob
robert campbell is offline   Reply With Quote
Old 06/02/2007, 01:06 PM   #3
Mosesatm
 
Mosesatm's Avatar
 

Location: Spokane, Washington
Joined: Jan 05
Posts: 7,351

Thanks Rob!
Mosesatm is offline   Reply With Quote
Old 06/02/2007, 02:11 PM   #4
68gt390
My Car Details
 
68gt390's Avatar
 
The car that became a diecast

Location: Columbus, Ohio
Joined: Feb 04
Posts: 2,021

Arlie;
Rob is right online. Even a lot of your big block cars are 28 spline even though they have the 9" rearend. It depends on your gear ratio. The easiest way to identify them is look at the end of your axels - they have an oval shape to them. If they are hollow on the end they are 28 spline and if the oval is filled in and solid they are 31 spline if that makes sense to you. That's how it was explained to me. Again, it would all depend on your rear end and gear ratio.


Don

68 GT/CS 390 "S" Code, 4 spd, 93 LX Hatchback Supercharged
68gt390 is offline   Reply With Quote
Old 06/02/2007, 02:27 PM   #5
Mosesatm
 
Mosesatm's Avatar
 

Location: Spokane, Washington
Joined: Jan 05
Posts: 7,351

Here is a link that shows the differences you are talking about Don. Makes it pretty easy to tell the difference!

http://www.metropartsmarket.com/rearend/measure.html
Mosesatm is offline   Reply With Quote
Old 06/02/2007, 06:45 PM   #6
gt bandit
My Car Details
 
gt bandit's Avatar
 
Down Under Thunder

Location: Perth , Western Australia
Joined: Nov 05
Posts: 460

Most 1968 J code cars with 3:1 ratios or higher are 9" 28 spline axles.

68 J/R code special - 2007 Turbo Territory - Mercedes CLK 2008
gt bandit is offline   Reply With Quote
Old 06/03/2007, 08:08 AM   #7
68gt390
My Car Details
 
68gt390's Avatar
 
The car that became a diecast

Location: Columbus, Ohio
Joined: Feb 04
Posts: 2,021

Arlie;
Thanks for posting that link. That's got some good info on it.

Don

68 GT/CS 390 "S" Code, 4 spd, 93 LX Hatchback Supercharged
68gt390 is offline   Reply With Quote
Reply

  CaliforniaSpecial.com Forums > GT/CS and HCS Forums > GT/CS and HCS Discussions

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 06:05 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2017, vBulletin Solutions Inc.


This site created, owned and maintained by Jon Hanna - Copyright 1996-2011
All rights reserved. CaliforniaSpecial.com is not affiliated with Ford Motor Company

ShowCase vBulletin Plugins by Drive Thru Online, Inc.