Sorry, I was really not interested in the combines and was talking to someone at the time.  I'm thinking someone said the 550 and both heads brought about $8,000 .... but I'm not sure that is correct or even in the ballpark.  I do know it and the 510 both were fairly cheap harvesting equipment if you could use a machine that size.

I was standing by a friend while they were selling the Unverferth rolling harrow, and elbowed him and durned if he didn't start bidding and almost bought it!  It was more or less $5,000 as I recall.  I was too surprised to pay attention!

Oh, and the IH semi tractor was in the $14,500 price range.  Good looking truck.