Bought new Oregon blades on Amazon for $49 for my 777 with 72" cut.

I thought when I got them that they were not that sharp and they were very, very heavy.  But then when I switched  to them I was very happy with the results.  They cut clean and I could run faster than with the blades I had on.  I kind of felt I wasted my money at first because the blades that were on the mower weren't dull or dinged up as I thought they would be.  I must have sharpened them last fall.