Ultrastangs Lincoln MKII conversion.

I was told it was an 8 inch.  How can I tell for sure

Quick and easy first check is to look at the center section under the car.  If it has a cover plate bolted to the back, it is a 7.5.  If the differential carrier bolts in from the front it is likely an 8"  Based on the post above, if it is Maverick four-lug, standard disc conversions will not bolt up because of the axle flanges, etc.  But before crossing that path, figure out what you actually have with a quick look under the car.  If it is indeed a 7.5 four lug, you wisest money would be spend locating a five-lug 8" if you intend to go V8 at some point.  A five-lug with drum brakes will be a wiser investment than putting discs on a rear end that you will scrap anyway.  Why the need for discs now?  What do you have up front?  What wheels do you intend to run?  This will determine the maxium rotor diameter and caliper combo that you can use that will still fit inside the wheel.

Here is a link that shows 7.5 and 8 assemblies and a nice looking 8" rebuild with drum brakes.  http://68redmustang.blogspot.de/2010/12/rebuilding-rear-axle.html

Last edited by GPatrick (6/02/2014 9:32 AM)

I put 92-95 crown vic/Town car/Grand Marquis on my 8".....do a little reasearch before you choose...the Mark-VII I've heard are a pain to adjust. The ones I've got was pretty easy to install, but I did have to fab some brackets and weld them in place. The Ebrake shoes on the set up I have are a real pain to remove/install I found out last night.

From the picture, it is definitely NOT an 8" rear.  I would not spend another $5 on that rearend. They are known to be very weak and parts for them are scarce.  You can find a good used 5 lug 8" rear end for a very reasonable price.  One from a 67-70 Mustang or Cougar will fit perfectly.  Then take a look at the MustangSteve COBRA-RSM rear disc brake conversion or the GT2008-RSM conversion.  It bolts up to ay 8" or 9" rear end.  You must have at least 15" wheels.

a 8" rear end will look like this forgiving of course that this one is a 4 lug maverick axle you will want one out of a car that mustang  steve has laid out. other then the 4 lug bolt pattern and disc brakes. this is what you are looking for.