Big differences between Orange and the Black Adjustable ones: Black heads you could adjust the individual row widths 2 inches wider or narrower, ie, an A430 could be set for 28, 30, 32 inch rows. Just slide the units on the toolbar, and reconnect units with different length drive couplers.
The 66H cross chains (about 6 feet long, considerably shorter than 4 miles) that drove the Orange row units were replaced by drive shafts that drove all the row units.
Sheet metal was punched to allow the 2 inch variance in row spacing. Sheet metal was hinged to flip up for easy access to adjust gathering chains.
Individual row unit components were identical, whereas Orange heads had several different snapping roll shafts, depending on location and function in the head.
Adjustment of the stripper plates was much easier on the Black heads. Oil-filled gearboxes were eliminated.