When they went to the 770/880 a lot of little things changed. Remember the 770 uses the 880 front frame and sheet metal. With the power booster only one bellhousing was used, the number of teeth on the flywheel ring gears was now the same for a gas and diesel as well. That is why a late key starter off of a Super will not work on a 770 or 880 due to the number of teeth on the ring gear. Does that help?