1965 GT350 Axles

[shelbydoug]

The bearings for the differential inside of the differential carrier are for the differential. They have little or nothing to do with the axles.

The 28 spline axles are 31 spline axles turned down to 28 spline size on the ends. As far as I know, they take the same axles bearings on the banjo ends.

I think that this has been covered previously. There were no 31 spline locking differentials available until the '68 model year. Even 67 GT500's had open differentials simply because there were no locking or limited slip units available yet.

I would have to say that there is a high likeliness that Ford Engineering anticipated this because of using the thicker 31 spline axles that were machined down to take the smaller 28 spline differentials.

Even the race cars initially used the 28 spline lockers/Lokers. As with most race cars there is evidence that most serious teams would have eventually switched over to the stronger 31 spline assemblies.

The saving grace really is that the 28 splines were running behind a 289. Those can hardly be considered high torque or even high powered engines. An FE of any kind would in short order strip out the splines.

So the answer is, you should be able to swap over to 31 splines with little or no concern. I think all of the axle bearings stay the same. ;

[cushmancomp]

I knew with Cory and Randys help we would solve this mystery.  I remember doing all this before the internet the hard way and it took years.

[sg66]

They look legit HiPo.  Any markings on the outside ends, on the extension that passes through drum?

Cory

Just for reference, a C4 number

[gt350hr]

   Doug
     FYI , Ford had Detriot Auto Products ( DAPCO , as in Detroit locker) create 31 spline Detroit Lockers in mid '63 . The '63 Galaxie lightweights were breaking axles and an improved 31 spline version was made. Ford knew the Equalock was not up to the task and that the Detroit locker was the way to go. For '64 the 31 spline axles were made for the Thunderbolts as well. For '65 and 66 the axles were made for the A/FX Mustangs . The first "production" cars to receive 31 spline axles were "some" '65 Thunderbirds an Lincolns. The only Equalock ever made for 31 spline axles was for the '66 9-3/8ths differential. For '67 the 427 Fairlane and GT500s got 31 spline axles and yes they were "open" as the Detroit locker was an "over the counter" item only. It would not be a "production option" until '70. Ford's traction lock ( clutch type unit) was first available in '68 in two and four spider 28 spline or 31 spline ( four spiders only).
   Ford had different forging "blanks" for axles and machined them according to the engineering call out. They didn't take finished 31 spline axles and remachine them to 28 as some people think. The induction heat treating process would not allow this.
   Cory's picture is of the "heavy duty" C4OW numbered axle used initially in manual transmission equipped Mustangs. The "medium duty axle had C2OW on the end and was initially only used on automatic equipped Mustangs.  All "production" Mustang 28 spline axles through '70 ( for certain) had the "oval" shaped end as in Cory's picture. '71-73 saw the evolution to two round drive pin holes.
     Randy