check out Harvey Bish's website. He is in the "attachments" column at the left. He converts row heads to a 22" I think. I must tell you, these things soak up a lot of horsepower. They will require a ton of maintenence if you don't convert to all spring loaded chain tighteners. Parts are easy, buy all old heads you can at farm sales. 4 rows are really dirt cheap. Good luck..GS