There may be a little confusion with the sprocket tooth count and the operators manual when you get everything together. Early 7000 planters used cast sprockets with a large tooth that fit the 2040 chain link. Later ones used steel cut sprockets that were supposed to drive a little smoother. Still used the 2040 chain. Just be aware if the operators manual is newer than the planter, or the other way around, the diameter of the sprockets is still the same regardless of the tooth count. Pay attention to your tractor drawbar height setting for level operation of planter frame. Be sure and have some seed graphite lube on hand and your good to go. What size planter do you have?