Can’t get Harland sharp rockers to fit on head?

Yep... back off the adjusters ...tighten down the shafts.... then set the preload. If you can't get the shafts all the way down with the adjusters backed out you need custom cut pushrods... two threads showing on the pushrod side is the recommended setting.

http://www.hughesengines.com/Upload/productInstructions/LengthCheckerMay20162.pdf

http://www.hughesengines.com/Upload/productInstructions/LifterPreloadFeb2016.pdf

http://www.hughesengines.com/Upload/productInstructions/RockerArmBundleMay2017.pdf