From my poor memory, and you can always look under the amp in a Leslie
251 to make sure I am on the right track.

Pins 1 and 6 are the audio pins for the flutes.  Pins 3 and 4 were the
AC power lines.  Pin 2 and 3 are connected to the speed switch for fast
and slow rotor speed.  Pin 5 was for the second channel in the amp
usually for reed type sounds.  I think the audio was just taken right
off the speakers in the organ.

It's been over twenty years since I last worked on one of those.
I will take it off you hands if you want to sell it.  I can easily
convert it to work on a Hammond B-3.

Don Teach, Shreveport Music Co
1610 E. Bert Kouns, Shreveport,  LA  71105
dat-smc@juno.com