Thew were offset to run with the 410 and 510 combines. These combines had 90" wheel spacing, and they were offset so as the wheels would run between the rows. Are you sure that the feeder opening is to the rightIJ or is it to the left side of the hesd. I Seem to remember that they were offset to the right. I had a 510 with 63 not 63c an the head was offset to the right. When the 750_760 came out the 63c came out. With your 860 you will have clearence on the left side, But on the right side your Machine will stick out two rows wider than the head. It will work, but you will only be able to combine around the field, not up amd back. Joe