HAHA , I am looking forward to setting up my SDS! In the instruction manual I remember seeing that they had a base curve for injector cc vs cyl displacement. I am guessing you could figure out how far off that curve you are with the injectors now , then set up the new curve off of the 680cc injectors. You may want to do it a different way , but this is my thoughts on it. hope this helps. laterz
~Kenny