On further checking, the book "Ford,the Complete History" by Consumers Guide, says that "Equa-Lock" limited slip became a Ford factory option in 1959. So any previous models equipped with limited slip, may possibly have been over the counter, but are more likely an after market install.    

Paul

I'll see if I still have the box. I think the old parts are in it. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Out of curiosity,what is the part number of this unit?I'd like to have one if I ever come across one.

 

Paul,

Boonville,MO

It is 28 spline. I suppose it could be a Ford dealer installed option. The Ford box and part number made me think is was available from the factory. Anyway, it is Ford and it does exist! Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Oh.  So now it's an over the counter part, customer or dealer installed, not a factory installed option?  Guess that's why it's not broken down in the parts book.  By the way, there must have been two of them, '49-'55s had 17 spline axles, '56s had 28 spline.

John

John - "The Hoosier Hurricane"

My posi in my 56 came with a Ford part number in a Ford box. It was a drop in install. This was made by Ford for the 49-56 type rear ends. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Now I'm going to add to the confusion.  First, I don't see any parts listed in the Ford parts book for a limited slip before 1958.  I checked with my friend in the Studebaker Drivers Club, his Dad was also a Packard dealer in the '50s.  He has a bulletin from Packard dated Nov. 1955 announcing a limited slip available in all '56 Packards.  They were available in all Studebaker lines in '57.  These cars all used Dana rears, so their parts would have fit the early Fords that used Danas, such as wagon, police, pickups.  Whether or not anyone figured that out in '57 is unlikely, unless they worked at Dana.  Paul, tell your adversary to "stuff it", GM did not invent the positraction, they copied it from Packard.

John

John - "The Hoosier Hurricane"

Yes, the posi rear end from a 57 Vette would bolt right into a passenger 57.In 57 the Vette and passenger car were almost identical under the fiberglass.You are on the right track.A lot of 57's had Vette rear ends transplanted into them,including my brother's and my best friend's.

 

Paul,

Boonville,MO

Sorry about the duplication, tired, past time to go to bed I guess... 

Paul

Interesting arguments, gentlemen!  Personally, I've never seen or heard of a 55 or 56 Ford that had a stock limited slip rear. But, getting back to G.M.'s Positrac, would the 57 Vette setup fit a 57 sedan?.. The point I'm trying to get at is that I strongly suspect that some of the vaunted performances of 57 Chebies (real or imagined) may have been assisted by having limited slip rear ends, at some point, that their competitors did not have, whether legal or not... Remember, stock class 57 Chebies somehow in the hands of the omnipotent NHRA, became legal with 4 speed transmissions at some point in the early 60s. Even though none ever came from the factory that way!   

Paul