Mustang II spindles fits on 1971 pinto?¿?¿?
 

The short answer is no without fabrication. The MII (same as 74-80 Pinto) spindle is about 7/8" taller (between the ball joints) than the 71-72 spindle.  I suspect this would affect the geometry.  One concern is increased camber gain on bump.  However I seem to remember somebody here installing the MII spindle in a 73 without complaint.  Another problem is that the hole for the tie rod end is larger in the MII spindle than the 71-72 spindle.  The 73 has a unique rack which uses the larger tie rod end, so the referenced person did not have a problem with this.