Great information. Since posting this question I have spent a few hours online and have also gathered some good information (I do however appreciate the first hand experience information).
(Versailles, Granada, Monarch)
Converting to rear disc brakes by using a Lincoln Versailles rear end on early Mustangs has become very popular. But, it doesn't just fall right in! Below is a list of things you'll need to do to make this swap an easy job instead of a hair pulling disaster!
Lincoln Versailles rear ends are also the same as was used on the Granada and Monarch.
Don't limit your searching to Lincoln Versailles only. From 1975 to 1979, many Granadas and some Monarchs were equipped with the same basic unit.
Make sure the locating holes are the right size.
The holes in question are designed to keep the rear end assembly from moving around on the rear leaf springs. The pins on the rear leaf springs should be the exact same size as the holes on the pads of the rear end. We have seen, usually on Versailles rear ends, much larger holes which will allow the rear end to walk around on the springs. If you have the larger holes, make 2 plates out of .125 or larger plate stock, drill the correct size hole for the pin, and weld them onto the bottom of the rear end pads.
Gear ratios are not desirable.
The lowest gear ratio offered in these units was 3:00 to 1. Most are in the 2:47 to 1 range and were available in a traction lock as well as open. All were 28 spline with very beefy axles. The good news is that any 28 spline 9" center section will drop right in.
Differential yokes are not compatible.
The Lincoln differential used a different yoke than the Granada and Monarch. This makes no difference if you plan to change to another center section with lower gears.
Shock plates need to be modified.
The axle tube on these rear ends are a much larger diameter than the stock Mustang and were all set up for staggered shocks which means that the shock mounting plates that come with them will not work on the early Mustangs. We have found that the simplest solution to this problem is to use 1965 or 1966 shock mounting plates and to simply slot the holes to the proper overall width for the u-bolt. None of that welding up and re-drilling! We have run these on the race cars for years with no related problems.
Check the rear brake line to shock body clearance.
The angle at which the rear brake hose comes off the axle tube is such that it may hit the body of the left rear shock absorber on bumpy roads, especially on lowered cars. Be sure to check for this problem. If it should exist, it's easily corrected by loosing the bolt on the hose and turning it more to the right. To get the best angle, you may need to bend the hard brake lines that come off both sides of the hose. This is easily done by hand.
Emergency brake hook up.
This is easier to do than to try to explain in writing, but here goes. Keep the parking brake cables that come with the disc brake rear end and attach them, as they came off the donor car, to your Mustang with enough slack for up and down movement. Using your old parking brake cable, attach a portion of it to both ends of the disc brake rear ends cables and cut off the excess. Any hardware store has cable connectors available which will do the job.
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