Yield monitor can be put on anything-but prob easier on this one because it has an 8820 clean grain elevator on it. It was on it when I got it.
I was told the key to bin extension is the dishing in of the wheels-to keep weight properly centered over the finals. I had to have 1 final rebuilt but it has been running that way for many many years with no problems.
In beans I never put more than about 180bu on there-but on corn we push it up to 300 on the long rows.
If anyone still has any Successful Farming magazines around from the mid to late 1970's there was an article in one about the Keller's near Blairsburg, Iowa who had made a 400 bushel grain tank on a 7700. They also strengthened the combine frame to carry this extra load.