From another forum, see #10:
I am owner of CSRP and operate the website
http://discbrakeswap.com .
I have a lot of experience with 60's and 70's Ford spindles. Here is my guide for classic Ford based on the Falcon chassis.
There are a lot of opinions, right and wrong concerning the disc brake swaps for 60s and 70s Ford. I have made it my business over the last 15 months to get to know these systems.
Spindle Types (more properly called steering knuckles).
Many of Fords compact and intermediate car line in the 60s and 70s were based on the Falcon chassis. These included Falcon, 65-73 Mustangs, Mavericks, Granada, some Torino, some Fairlanes, the Mercury cousins, and others. The basic suspensions in all of those cars are the same, with minor differences in outer tie rods.
60-80 Falcon Chassis models had at least 12 varieties of spindles.
1. A light weight 60-62 drum spindle used on Falcon/Comet.
2. A light weight drum brake spindle used with 6 cylinder cars 63-66. Used on 64-66 Mustang, and on 63-65 Falcon.
3. A 63-66 drum spindle which was adapted for disk brake use using a bracket. This is the 8 cylinder spindle and is relatively lightweight and was originally designed for 10" drum brake application. This spindle has slightly different steering arm/tie rod geometry than all future Falcon based spindles. This spindle uses a slightly larger outer tie rod mounting hole than the previous types. This was used on 64-66 Mustangs, and on 63-65 Falcons.
4. A 66-69 drum brake spindle which was adapted on 67 Mustang and 66-67 Falcons for disc brakes using a bracket. This and all future types are used for all engine applications, 6 and 8 cylinder. This spindle and ALL future Falcon series spindles have the same steering arm/tie rod geometry. These spindles are slightly beefier (except for the spindle pin itself) than the other 63-66 type. This spindle uses a slightly larger outer tie rod mounting hole than the previous types. This was used on 67-69 Mustangs/Cougars, and on 66-69 Falcons/Comets and Fairlanes, and 68-69 Torino.
5. A 68-69 purpose built disc brake spindle which used a sliding type single piston caliper. Essentially the same weight as the 66-69 drum spindles. Uses an 11.25" brake rotor. This spindle uses the same outer tie rod mounting hole as the 66-69 drum type. These were used on 68-69 Falcons/Comets, Mustangs, Torinos, Fairlanes, and Cougars.
6. A 70 drum spindle for which I cannot find info that distinguishes it from the 71-73 type. This was used on 70 Falcon, 70 Mustang, 70 Torino, 70 Fairlane, 70 Cougar, and 70-74 Mavericks/Comets. This and all subsequent spindles have a larger pin. It also has a slightly larger outer tie rod mounting hole than the previous types. A variant model used on 75-77 Mavericks/Comets, and 75-80 Granada/Monarchs uses an even larger outer tie rod mounting hole (same size as later Granada/Maverick disc spindles do).
7. A 70 purpose built disc brake spindle for which I cannot find info that distinguishes from the 71-73 type. This was used on 70 Falcon/Comet, 70 Mustang, 70 Torino, 70 Fairlane, 70 Cougar, and 70 Maverick. It also has a slightly larger outer tie rod mounting hole than the previous disc brake type.
8. A 71-73 drum brake spindle. This spindle was used on 71-73 Mustangs, 71-73 Cougar, and 71-74 Mavericks/Comets.
9. A 71-73 purpose built disc brake spindle (larger pin like with 70 model).It uses the same bracket and caliper as the 68-69. It uses the same rotor as 68-69. This was used on 71-73 Mustangs, 71-74 Cougars, and 71-73 Mavericks.
10. A purpose built disc brake spindle which was essentially identical to the 70-73 models except that it uses a floating type single piston caliper and associated bracket. The outer tie rod mounting hole is larger than the 70-73. This spindle was used on the 74-77 Maverick and the 75-80 Granada (several million were made). It uses an 11" rotor.
11. A purpose built disc brake spindle used only on the 77-80 Lincoln Versailles. It is identical to the Granada except that the lower ball joint mount hole is larger.
Mustang II and Pinto used a different type of spindle but the same calipers as the Granada/Maverick.
All 12 of these Falcon based knuckle/bracket systems used the same spindle to ball joint geometry and yield the same hub face to hub face width.
IMPORTANT NOTE Spindles types 3-11 have identical steering geometry! The steering arm for #1 and 2 (65-66 Mustang, 63-65 Falcon) are slightly different.