8 INCH 31 spline !!!! WHAT

[TOM B]

I thought all 8 inch rear could only accept 28 spine axles, well look at this.

http://cgi.ebay.com/ebaymotors/Ford...018QQitemZ280099405175QQrdZ1QQsspagenameZWDVW

 

[351w_swap]

They aren't stock and they could be used in a spool from moser or one of the other rear end companies in an 8 inch. It also states that they could be used in 9 inch and 31 spline is common place in 9 inch rear ends so it is not unexpected that the add is true.

 

[TOM B]

So a 31 spline axle will fit into a 8 inch rear, not so as per Ford Muscle magazine

http://www.fordmuscle.com/archives/2003/03/project67/

 

[D.Hearne]

Yea they'll fit. I've got 31 splined axles with the small bearing Fox body Mustang/Ranger bolt patterned axle ends. (although they weren't what I wanted) So in other words the 31's will fit thru a small bearing axle housing.

 

[rbohm]

as i recall the side gears that the axles fit into are the same between the 8 and 9 inch rears, and the 31 spline axles are only slightly larger than the 28 spline axles. you will need a special axle bearing to fit the larger axles in the smaller ends. but 31 spline axles will fit the 8 inch rear.

 

[ratio411]

I can see them fitting.
The "big" 8" bearing is the "small" 9" bearing.
I am sure someone made small bearing 31 spline axles.
Then you just swap 31 spline collars into the 8" diff.
The collars swap, and 28 spline 8" is 28 spline 9".

Now, why would someone do this?!?!
The 28 spline axles are not known for breaking in an 8" rear.
They are the strongest part in that unit.
There are a dozen other parts in the 8" that will break long before an axle!
Big waste of money!
With the cost of aftermarket 8" parts, the ones that need upgrading, you will spend the same or more than just getting a mild 9" that will be stronger...

 

[rbohm]

The "big" 8" bearing is the "small" 9" bearing.

uhmm i have never heard of a "big bearing" 8" rear end. to my knowledge all 8" bearings are the same size.

 

[ratio411]

uhmm i have never heard of a "big bearing" 8" rear end. to my knowledge all 8" bearings are the same size.

4 lug 8" rears generally use the small 8" bearing.
Don't know about Stangs or Falcons, but this holds true for 4 lug:
Maverick/Comet
Pinto/Bobcat
Stang 2

You cannot swap one of these cars to 5 lug by just putting in 5 lug axles due to the large vs small bearings.

 

[TOM B]

Here's why I want to stay with my 8 inch.
1) I already bought a Power-Trax locker in 28 spline and it works great.
2) have 1 year old 3.55 gears in it now.
3) just to lazy I guess.
So I already have some bucks in the 8 inch so My next purchace will be Hardened 28 spline axles from Moser or Dutchman. Should hold up since I have no spiders to break