What exactly do you mean by won't handle stalksIJ Make sure that snapping plates are open far enough to let the stalks enter rolls easily. The center distance of the rolls is also adjustable at the front. RH roll must be perpendicular to the gearbox, lH roll is used to adjust spacing for larger or smaller stalks(corn head manual). The stalks must be able to enter the roll easily, but the rolls must be close enough to maintain traction on the stalks. If shredding is your concern, roll condition, speed and operating height are the things to watch. MF offered slow down sprockets(35 teeth) as an option for down corn (32 teeth standard). Someone in our area built 30 teeth sprockets to speed rolls up, but this takes more power. Check combine rear beater speed and adjust as necessary. Remember not to let beater speed drop too far under load (700 rpm minimum),as the head slows down with it. If corn is that heavy, slow ground speed. Also make sure header clutch is locked up, as in the manual, and not slipping