I agree with aged1440, if you want a 16 row hd, have one built. Brad Bish out of Giltner NE does a good job of fabricating large heads as does Clarke Machine out of Howard SD. I've seen finished products from both shops and they are done well. Bish just finished a 16 row 30" crop head to be mounted on a CR 960 NH to cut soybeans in central IA. Clarke Machine built a 16row 30" corn hd 3 yrs ago for a custom harvester in SD mounted on a 9750 JD. They can do it.