Hello John and welcome to the forum. Here is my engine with chrome valve covers. Inside is a .609 lift HR cam with Harland Sharp rockers. To help with clearance , Fel-Pro make a thicker valve cover gasket . You also need to bend up the splash guard under the oil filler tube. To use a hydraulic roller cam in a 260 block call the cam companies ,they make Cam/kits for early blocks. Good luck , Hugh