Needed same. Used Kucher High Performance Parts.
507-327-3693
300 IL  Rt  4 S
Garlinville IL 62626

Also used his chaffer upgrade. 
Bars will do corn without filler plates/bars.

Works great. Run in Corn, Beans, Wheat & Rye. 
   (small grains with stripper header.)

Can't tell the price- been a couple of years.
Wish I had done it earlier, but I procrastinated until I had a damaged bar on cylinder.

First saw his products at Nat Farm Machinery Show, Louisville KY