coveted "black" motor

[mitchberry]

what's the difference between the coveted black motor and other motors.. say, the one that comes in a 78 cb750K?

[Re-run]

The black motors are the F motors. There are some differences but really, the 78k engine is mechanically more sound. The 77/78 f has a good engine except for the valves. They wear out quick cause of the angle they used.