Here is the Comet/Falcon/Ranchero front spindle breakdown as best I know it (if anyone sees an error please correct it). All cars had 6-cyl only until '63.

• 1960 production dates - 10-16-1961 prod. date
  • small upper & lower balljoint. 4-bolt lug pattern
• 10-17-1961 prod. date - late 1962/early 1963 prod. date (3-rivet upper ball joint)
  • small upper and large lower ball joint. 4-bolt lug pattern
• late 1962/early 1963 prod. date - end of 1965 model year (6cyl only) (4- rivet upper balljoint)
  • large upper and lower ball joint. 4-bolt lug pattern. *
• late 1962/early 1963 prod. date - end of 1965 model year (8cyl only)
  • large upper and lower ball joint. 5-bolt lug pattern.
• 1964-1965 mustang (6-cyl only)
  • large upper and lower ball joint. 4-bolt lug pattern. *
• 1970 - 1976 Ford Maverick/Mercury Comet (6-cyl only) (these came in disc & drum)
  • large upper and lower ball joint. 4-bolt lug pattern. * #

* all of these are a direct bolt-in replacement for each other so long as you use brake/bearing parts appropriate to the spindle donor car.

# swapping disc spindles for drum spindles will require changing the M/C to a disc/drum M/C & adding the appropriate proportioning valve.

You can swap any 6-cyl spindles to other years by changing the upper and/or lower control arms (which may require changing the strut rods as well). V-8 spindles swapped for 6-cyl spindles will require upgrading many more suspension/steering components.