The JD is a good head, the only real benefit that i see is that the 1063 has the roller knives that do a better job of chopping the stalks and if you have a problem with tie-vines, the knives are alot of help.
Bish makes the adaptor to make it work. The JD head has one nice feature: no lower bearings to deal with. The Deere heads are as trouble free as anything can be with minor maintenance. The IH head will probably chop the stalks better. I had an 844 and there was a lot to be desired with the support bushings on the rolls etc.. I also had feeding problems at the front end when the stalks got damp or if in grassy conditions. The newest IH head looks like a winner but that's apples and oranges. For what it's worth I'd keep the JD head unless you get a super deal on the IH head.
keep the jd head the money you save will soon pay for the adapter if you don't want to make one your self just the reliablity and been so easy to work on makes them a winner