Most of you already know the 71-3 Mustangs with variable-ratio power steering used the General Motors Saginaw box. I would think the pump is Saginaw too but not sure? Here is a related article from Hemmings Motor News:
http://www.hemmings.com/mus/stories/2007/09/01/hmn_feature21.html
Here is more info from the Ford Facts Book used by the salesmen to help show the spec and features of these cars:
MANUAL STEERING
Mustang's manual steering system is a parallelogram link age type with a cross link and idler arm. This system offers more positive control of the car under all driving conditions with a minimum of steering effort. Features of the manual steering system include:
Cross-link bar positioned to improve directional stability and reduce oversteer.
The steering shaft control assembly is driven by re circulating ball bearings in a closed channel for reduced friction. The "Magic-Circle" steering gear is filled with a life-time lubricant which never needs changing under normal circumstances. See page C-22 for steering specifications.
POWER STEERING
A new power steering system is optional on all 1971 Mustang models. The system utilizes the standard manual steering linkage and Ford's "Better Idea", "Fluidic Con trol" power steering pump that supplies extra power when you need it and "coasts" at high speeds. Functioning through a unique, patented "fluidic" control, the pump forces the maximum amount of fluid through the system at low speeds for easier parking. At highway speeds, it reduces the fluid flow to provide a good "feel" of the road and save on engine horsepower. Other features of the unit include:
Power unit integral with recirculating ball steering gear.
Integral control valve provides instant response to wheel movement.
A torsion bar element is used in the steering shaft to provide a precise feel of the road.
An overall steering ratio of 21.8:1 provides fast responsive steering.
3.9 turns of the steering wheel lock-to-lock is 12% faster than manual steering.
VARIABLE RATIO STEERING GEAR-a variable
ratio steering gear is provided when power steering is ordered on a vehicle equipped with the competition suspension. With variable ratio steering, a special gear is used that gives a rapidly reducing ratio as the wheel is turned beyond center. This gives the driver the benefits of quick ratio steering without the steering being super-sensitive. Quicker, more responsive steering and handling is a result of this steering/suspension combination.
POWER STEERING
A new power steering system is optional on all 1971 Mustang models. The system utilizes Ford's "Better Idea," "Fluidic Control" power steering pump that supplies extra power when you need it for parking, and reduces power flow at highway speeds to provide a good "feel" of the road and save on engine horsepower.
The power steering option includes a variable ratio gear on models equipped with competition suspension. ]
STEERING SPECIFICATIONS
Linkage . . . . . . . . . . . . Parallelogram with cross-link
Gear Type . . . . . . . . . . . . Recirculating Ball and Nut
Overall Steering Ratio
-Manual 27.7:1
-Power 22.1 :1
Steering Wheel Turns (lock to lock)
-Manual 4.46
-Power 3.94
-Power Variable Ratio 3.17
Turning Diameter (curb to curb) 39.8
Steering Wheel Diameter 15.0
Constant Ratio Power Steering except with competition suspension. Variable Ratio included with competition suspension @ 15.7: 1 overall steering ratio.
Ray