Did you try flattening your head? If you don't have an adjustable feederhouse maybe someone on here knows of a wedge kit that could be installed.  
Also I got a bigger driver sprocket each end of my 8 row hugger, think oem is 16 or 18 teeth and went to a 22 or 24 tooth.
Plus you might put stalk stompers on every row which breaks the stalks over at the ground and helps speed up decomposition.