It WILL run a 20' head in 60bpa wheat.We are nearing the end of a muddy wheat harvest and the 642 that my father runs decided it was done for now.The transmission is destroyed in it due to a freak mechanical issue.The parking brake drum runs off of the end of the trans main shaft and aparrently either mud or weeds partially applied it.Before my father caught it the drum was scalding hot and destroyed the seal right behind it.Most of the oil ran out and the bearing right behind it came apart and wound up in the trans gears.Pop said he noticed it pulling a little hard before it failed but thought it was just the soft ground we were on.I do have another trans but it is at least a two day job to change it(both big tires and final drives need to come off to change it).I had the Dominator sitting ready but did not have a smaller head for it so I decided to try the 20' head on it that I rebuilt last year.I figured we only like about 50 acres so if he only could use half of the 20' he would still be helping.To my suprise the little 76 handles the big head with ease and is doing a GREAT job.This is the first time I have ran it in wheat and to tell you the truth the Dominator is VERY closely matched to the 642 in wheat.THe extra 30 horses from the Mercedes keeps it chugging right along when the 642 runs out of power in really thick wheat.This is one case where it was real nice to have a spare combine just sitting when I really needed it.