you've ever wanted to know about Ford 9 Inch Differentials!
Inch Pinion Supports
Ford differentials, similar to the 9"
9 1/2" story..
Here is something else you may run across, a 9 3/8"
ring gear housing(sometimes called a 9 1/2" Ford carrier),I don't
know much about them, but looking in the book they appear to have
come in the larger Lincoln and Mercury vehicles.Note casting number
C8AW-4668-B on pinion support and the double ribs(spaced further apart)
with the end bent down on one.From what I understand parts from these
rears do not interchange with the 9 inch carriers.
The younger brother to the 9 inch, the Ford 8 inch is an identical
design, but on a smaller scale. Generally speaking the 8" will
not handle the abuse of the 9", and is good to about 300 lb.ft
of torque under high-stress. It can only be fitted with 28 spline
Shown at right is a 1966 and earlier case, with only horizontal ribs
and no fill plug. (C20W-4025-F)
improved carrier for the 8" found in 67 and up. Note the fill plug
in the case, as well as the vertical reinforcement ribs. If you must
build an 8" for any amount of abuse, get this case. It can be
found in a variety of models up to the late 70's Mustang II's.
the difference between 9" and 8" Axle Housings
above is the typical 1967 and up 9" (lower) and pre-1967 8" housing
(upper). Note no fill plug on back of the 67 and up housing, this
is true for the 67 and up 8 inch housings too. Earlier housings, like
the 65-66 Mustang 8" pictured have the fill plug in the back, this
is true for the earlier 9" as well.
of the ways many people spot a 9" rear end in the car is by looking
for the hump in the center of housing, this is not always the best
way, as 9" housings made prior to sometime in 1966 do not have the
this large center protrusion.The 9" shown above is out of a 63
Galaxie, note its roundish appearance, two dimples and fill plug in
is the 9" housing style familiar to most, note the large center
protrusion or simply the "hump" in the middle. Housing also has the
two dimples, but note lack of fill plug.This housing is out of an
little brother to the 9" housing is the 8" housing, note its more
oval appearance when compared to the above two 9" housings.This one
is out of a 65-66 Mustang, note the two dimples and fill plug.
area of concern when swapping axle housings into earlier Mustangs
(65-66 models especially) is the diameter of the outer axle tube.Note
the taper on this 8" 65-66 Mustang housing, a smaller U bolt and lower
shock plate were used originally with these cars.The HIPO 289 cars
were the only 65-66 Mustangs to recieve factory 9" axles, the tubes
are tapered as well at the end to utilize the same lower shock plate
as the regular 65-66 Mustangs.
this axle tube has no taper at end,as is typical for most housings.A
typical early Mustang swap is a later Granada housing, were the non-tapered
tube can become an installation problem at times.