Author Topic: 66 Rear end upgrade?  (Read 14311 times)


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66 Rear end upgrade?
« on: August 30, 2009, 10:34:59 AM »
Hey Guys,

This is my first post. I must say I am very impressed with the site. It seems to be vary organized and a ton of helpfull info.

I have a 66 coupe and have been wanting to repalce the rear end. I have the stock 8" 3.00:1 one leger with stock drum brakes. I am not sure waht my options are. I would like to go with a stronger rear end that has POSI and midrange gears (3.50 or 3.55).  If it had disk brakes that would be a bounes and another project to convert to.

I am running a some what built 351W with a 4 speed top loader and would like to make it a street/strip car on the weekends. Any advise or experance would be great  ;D 


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Re: 66 Rear end upgrade?
« Reply #1 on: August 30, 2009, 12:04:41 PM »
First off, welcome to the site. Depending on how much you are willing to spend, Currie has a crate rear end, its a 9+" rear end with both 31 spline axles, already assembled differential, your choice of drum or disc brakes, and it will bolt right up to your current shocks, and leaf springs like original. Hope this helps,a nd good luck.


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Re: 66 Rear end upgrade?
« Reply #2 on: August 30, 2009, 03:24:27 PM »
Or, you could go to a junk yard and steal one off of many different Ford makes.  Take a measuring tape with you though, because that 66 takes a 57" axle measured from spline to spline.  Most of the newer Fords had 60-62" axles.   Or keep your 8" and have it built with 355 gears and  a locker or limited slip.  That would be your cheapest route, and that 8" will work just fine without breaking even behind a 500 horsepower motor. 


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Re: 66 Rear end upgrade?
« Reply #3 on: September 01, 2009, 08:15:25 AM »
OH, I hate to promote another site, but he asked!
Check out the Lincoln Versailles 9" disc brake rear end swap into a Mustang article by Mustang Monthly. Here's the link

This is probably the most common swap done on early Mustangs.  It is the same rearend I have in mine.  You need to read the tag on the rear dif to determine the gears.  If I recall correctly, mine has 3L00 on the tag, meaning a limited slip (better than a posi and trac-loc for street in my opinion) and 3.00 gears.

I can't say they are HD enough for drag racing, but there is a 9" with disc brakes that fits an early Mustang.



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