[Washboard]

I've run out of leads in my search for a 620 power train, so I'd like to put out for some assistance.
Because of previous experience, I am only eligible for the 620 grid, so I am looking for a complete engine/electrics ensemble to put in my rolling chassis. I would prefer a complete, crashed bike, or an inexpensive straight one, but just a good engine and electrics will do fine.
I have a good, straight, undamaged 600ss and when I have the parts I need, I will be selling all the redundant 600 parts, but I won't be taking it apart until I have all I need to complete the 620 powered bike.
Any help/information/contacts will be gratefully received.
I live in the Bedford area, but will travel anywhere in the country.