You may have to invest in some different final drives, an additional lift cylinder, and some new feederhouse drive components. I'm pretty sure that you had to order a 12 row package to be able to run that head on an 8820.
You say that you want to use a 12 row head to control trafficIJ I think your going to have just the opposite effect. You're going to have a grain buggy beside you, because no way a 12 row head with 275 bu bin will handle 3_4 mile fields. You are better off with a 6 row head, and put wagons either on one end or on both (I don't know yields)
Ran a 12 row corn and 12 row row crop bean head on a 8820 (single tires) for 8 years it was one of the first 8820's out.Handled the 12 row ok in high yeilding corn.Just the hopper size was small and its a good idea to have a grain cart or two,but just depends on your operation.Might make sure that your combine is set up for it.