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Author Topic:   xr-7 9 inch
RACEINMUD
Member
posted January 29, 2004 03:14 PM
Hi, will a 1973 xr-7 Nine inch fit for my 79 Cutlass? Thanks, Race


outlawstock17
Member
posted January 29, 2004 04:59 PM
yes, that rearend is the perfect width for a metric car.


RACEINMUD
Member
posted February 18, 2004 03:39 PM
Picked up the housing and it is missing the left axle (drivers side). Anyone tell me what size I need for rearend. Thanks, Race.


RACEINMUD
Member
posted February 19, 2004 01:55 PM
Anyone?


outlawstock17
Member
posted February 19, 2004 05:24 PM
i'm not sure of the exact length but i can tell you what cars to look under. keep in mind that the donor car doesn't have to have a 9". 8" axles will work too unless you need 31 spline axles. look for 70-71 rancheros, 70-71 torinos/montegos and 71-73 mustangs/cougars. these car are sometimes tough to find. i've seen them on ebay occasionally.

good luck.

good luck.

flatfoot27
Member
posted February 19, 2004 07:27 PM
what kind of car did that rearend come out of? The xr-7?


flatfoot27
Member
posted February 19, 2004 07:29 PM
I never can really get a straight answer from anyone on which fords to look for to find these narrower rearends. Any help would greatly be appreciated.


outlawstock17
Member
posted February 19, 2004 08:59 PM
an xr-7 is a fancy cougar. it's not even close to the narrowest 9" from the factory. there are at least 2 others that are narrower. however, it fits the metric chassis better than any other factory 9".

[This message has been edited by outlawstock17 (edited February 19, 2004).]

20bmw
Member
posted February 19, 2004 10:23 PM
Here is a list of Ford 9 inch reae ends..
These measurements are from flange to flange. Subtract 5" for bare housing length.

65-66 mustang 57.5"
67-70 mustang 59.25"
71-73 mustang 61.25"
77-81 granada/versailles 58"
67-71 comet, cougar, fairlane 59.25"
64 falcon 58"
57-59 ranchero and station wagon 57.25" (narrowest 9" housing)

[This message has been edited by 20bmw (edited February 19, 2004).]

20bmw
Member
posted February 19, 2004 10:32 PM
The 63-77 lincoln, ltd, thunderbirds had 9.375 inch centers, housings were cut away at the gasket surface for ring gear clearance, one curved rib at the front top portion of the differential. strong, but no aftermarket gears for this rear end...


RACEINMUD
Member
posted February 20, 2004 08:19 AM
Flatfoot, It came out of a 1973 Mercury Cougar XR-7. Ok, Do I need a 29 3/4" axle or a 30 something. Thanks, Race


flatfoot27
Member
posted February 21, 2004 06:47 AM
Thanks alot, this is good information. I really appreciate it.


squid
Member
posted February 22, 2004 09:01 PM
so whats the best width to have. I was told 58, but i know guys that run 60's. whats the optimal length for a hobby.


racer17j
Member
posted February 22, 2004 10:25 PM
a 58 is what you want the 60 works but you have to limit the offsets you can use without the tires sticking way out


rufryd
Member
posted February 23, 2004 01:32 AM
the 56 1/2 housing from 69-72 ford 1/2 ton pickups seem to be the best, with big bearing ends and axles are the same 29 3/4" long so yuo don't have to carry but one lenght of axles


flatfoot27
Member
posted February 23, 2004 07:40 PM
Rufryd, Your killing me with this info. My neighbor has a 70 F100 sitting in his back yard. I've never heard this before about pickup rearends. I'll deffinitely check this out. Thanx


outlawstock17
Member
posted February 23, 2004 07:48 PM
if you use the truck housing and have to use the stock floorpan, you might have driveshaft to floorpan clearance problems. the pinion on these rearends is offset to the passengers side 2" from center.


toddr46
Member
posted February 23, 2004 07:48 PM
Would any other axles work in this rearend? And does the 9 inch rearends in the cars have offset driveshafts? Thanx


flatfoot27
Member
posted February 23, 2004 07:54 PM
Also could a guy weld these metric bracket's 2 inches off to offset this pinion angle?


outlawstock17
Member
posted February 24, 2004 05:51 AM
most ford passenger cars with 9" rears have the pinion centered. this makes the drivers side axle 4" shorter than the passengers axle. they can be centered under the car. the u-joints can handle the mis-alignment, if your floor pan can. i used this rear in a car that didn't require stock floorpans with no problems.

if you use the truck rear and center the pinion, the left rear wheel will be "out there". another "downside" to using the truck rear is the axle flanges are thinner than passenger car rears and you will need to do some machining on them. they have to be re-drilled, the OD of the flange has to be turned down, the drum/rotor "centering nub" will need to be turned down unless you use the truck drums and the back side of the axle flange will need to re-radiused to accomodate the smaller bolt circle.

i've also seen a LOT of these axles snap the flanges off on heavy/rough tracks. the re-machined axles are kind of scary, so i went ahead and plunked down the cash for a floater.

boas51
Member
posted February 24, 2004 07:28 AM
the 68 to 72 ford 1/2 ton diff is almost 62" flange to flange. 4" wider than a metric. i have used them and found them as good or better than most others, just a little to wide. you can offset the diff 1" to the left run a 5" bs wheel and run a 3" bs wheel on the right with 2" bs on the front. or you can widen the front of the car 4".
if you are looking for something that will fit the track width of the metric you will have to look at the older, weaker, car diffs, as listed.
i have heard the lincoln diffs are good, and some have disc brakes.


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