I have a set of the heavier duty 65-66 Shelby 28 spline rear axles. Very rare and correct me if I am wrong.
$800 plus shipping
Jay Cushman 207 749 3307
Quote from: cushmancomp on June 07, 2019, 12:07:48 AM
I have a set of the heavier duty 65-66 Shelby 28 spline rear axles. Very rare and correct me if I am wrong.
Can you please confirm they are 28 spline.
The HiPo and LoPo 289 axles are different. The HiPo axles have a larger OD over the LoPo axles, making the HiPo axle stiffer (less deflection) and stronger (can carry more torque), assuming the same metal alloying. In terms of fit, they are interchangeable, same 28 splines size, same bearing size, same length. These axles are typically not mentioned in literature as differences between a HiPo and LoPo early Mustang. You can use LoPo axles in a HiPo K-code 9 inch rear end. You can use a HiPo axles in a LoPo eight inch rear end. They are completely interchangeable. There are casting marks on the outside hub ends that are also different, but I can not remember what they are. Does someone else?
According to the Ford Master Parts Catalog both axles meet the same descriptions at 28 spline, RH 30 1/8 and the LH at 26 5/64. For 65/66 Mustang the MPC shows:
8 inch ring gear (LoPo) part numbers are C20Z-4234-A and C20Z-4235-A.
9 inch ring gear (HiPo) part numbers are C50Z-4234-B and C50Z-4234-A (This could be a misprint in the MPC, it might be C50Z-4235-A. Ford ID's parts left and right with a last
character change in the part number.)
See images below for differences and similarities:
Cory
The center section of the hub where the drum fits around is different on a 65. These center sections look more like the ones on my KR which are 31 spline.
What are the difference in outside dimensions?
they are 28 spline but are in my storage building in Cal for another month now and I am on my way back home to Maine.
I my have a pair of these and want to verify. Can the OP post the shaft diameter of these for reference please? Thanks! Jack
I measured:
LoPo 1.05 inch
HiPo 1.20 inch
Hope that helps.
Cory
But is there a nexus to SAI? I can't find any, perhaps I'm missing something?
They appear the same a Edsel axles (I'm not kidding).
Jay,
Production 28 spline '65 and 66 Mustang axles had a somewhat rectangular recess on the end of the axle ( used for turning ) instead of the "two drive pins" and centering hole. The A/FX axles ( 31 spline , I have two sets) did have the drive pins and may be why Charles is asking about spline count. If those are 28 spline , I believe they are from a drum brake Granada or Monarch. The rearing retainer plate and lock ring ( to me ) all point in that direction.
Randy
My rear appears to be out of a 57 or 58 Ford and has the 2 dimple housing with no drain plug. But the axle ends have the 2-holed (similar to 31 spline) appearance and I know this is not from the newer Granada, etc. I will pull the axles for further ID. Thanks for the measure...
57-58 axles were not that "robust" and the "hub" area was much shorter. Now that I think of it the Granada / Monarch drum brake axle had two "access holes " in the flange. It is a later axle than the '60s , maybe a Maverick.
Randy
Lets try this again......Can the real experts verify if these are the correct 65 66 Shelby and Hipo 28 spline axles? 26.250 and 30.125 long oversized 1.200+ shaft size. 1.180 right at machined area where it transitions into the splines.
They look legit HiPo. Any markings on the outside ends, on the extension that passes through drum?
Cory
2 questions ?
1. Shafts in first pic, at beginning of thread, show the ends (drum end) solid with 2 drill holes, but shafts pictured at the end of the thread have the 'typical' hollow ends seen on every 'Lopo' 28 spline shafts that I've seen. Are we to take it that a correct HP / Shelby shaft has the solid ends with the drill holes ? (I expect they are not drill holes, I'm just trying to explain their appearance). This way , would be easy to verify a correct shaft by merely removing a wheel, or if possible, a centre cap. And 31 spline shafts from 69/70 Boss have the solid ends too, so is that a manufacturing similarity denoting the 'HP' shafts ? Reading above, mention of drive pins and centering hole, which makes sense, I'm just wanting to know if that makes them correct, in which case the last pic, would not)
2. There is mention to the diameter of the HP shaft being similar to a 31 spline. Is it possible therefore to fit a (correct length) 31 spline shaft into a small bearing axle housing ? Something I've wanted to find out but have never managed to. As would mean, for example, a 31 spline 'N' case pumpkin could swap in with a pair of aftermarket shafts. Sorry this is a 'non-original' question.
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. ;
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.
Quote from: 6s1640 on August 18, 2019, 01:43:05 AM
They look legit HiPo. Any markings on the outside ends, on the extension that passes through drum?
Cory
Just for reference, a C4 number
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