If you have any issues with clearance of the rockers, you can contact
www.champpans.com and get a set that looks very much like the original stamped steel covers, and they will put as many breather tubes as you want. I believe they were well under $100. If you decide to go with the shorter covers and still have clearance issues, I have a set of 1/2" billet spacers from Mike Fortes that are available for $120.