I would put a 17.5 foot unit on it. That is about the largest unit you can go down the road with without a header wagon. If you can make your door wider to fit, that would be your best bet. The 1460 is really a 20 foot machine in wheat and soybeans and with a 17.5 foot header you can go a half mile per hour faster and still do a good cutting job. Any smaller and you won't keep the cage full and you end up with a poorer threshing job.