A friend of mine was going to modify a 28 spline 9 inch for me under my 86 TA. I did buy a detroit locker (truetrack) for 28 spline 9 inch. Now he is haveing some problems because of the length of the 28 spline housing he has and was telling me if we would use 31 spline housing it would not be a problem. Its ok with me but I have already bought $500 Truetrack for 28 spline housing and am not sure there is a huge market for it in Iceland.

Now I am trying to convince myself that I will at least get a better housing. Is the 31 spline 9 inch much stronger than the 28 spline?
Would I run into problems with the 28 spline 9 inch at my hp level (425 hp ZZ383)?

Well, it would be nice to know before I start spending money

 

There is no difference between a 28 spline and 31 spline housing. 31 spline axles fit the same housing as 28 spline axles.

 

I wouldn't recommend Ford 28 spline axles for any street car but since you already purchased the 28 spline Truetrack, you might as well use it. Ford used 28 and 31 spline axles in their 9". The only difference was the carrier (posi).

 

Well I decidet to buy a 31 spline 9 inch. I will just have to try to sell the truetrack I currently own and buy another one for the 31 spline. Hopefully I can sell the 28 spline housing for a similar price as the 31 spline did cost me (but I am sure I will loose a lot of the truetrack).

At least I should have a bulletproof rear end that will never break.....

 

He's exactly right theres no difference between the housings... who ever told u that really dont sound like they know what they are working with.. the only difference with the 9" houseing usually is they made a few different size axle bearings.... but spline count has noithng to do with the size of the housing. best of luck

 

The size of the carrier bearings will limit the axle size. The smallest factory bearing will still handle 28 and 31 spline axles and should even be able to use aftermarket 33 spline axles. Aftermarket center sections which use larger carrier bearings can use 35 or 40 spline axles.

You'll just need a new carrier designed for 31 spline axles and some 31 spline axles.

It's not really bulletproof. The C7AWE center section has it's limits but you either need a heavy vehicle or get into the 9's before it starts to fail. The pinion pilot bearing support can crack and break off. If it does, it will shoot the pinion out the side of the diff.

I found mine cracked before it had a chance to fail. I upgraded to a Moser bolt through aluminum center section and a Daytona pinion support. With an aluminum center section, pinion support and spool, only the gears and bearings are steel. I can put the center section in with one hand.