mic
Guest
We don't run a 6620, but have a 7700 and 9500. We run a 220 on the 7700 and a 925 on the 9500. Both machines could take larger heads, but mobility becomes a concern. The 220 is the best for running down the road with the header on. We move the 925 on a header cart. The smaller head saves the time of dropping the head on a cart, then towing it along. I would guess that a 20 foot head would go good on the 6620. I personally would not go larger though. Especially if you have the chance of running in tough conditions (weeds, green material, etc...) You could definately plug up the cylinder in a 6620 with a 20 foot head.