I AM RUNNING STAGE 6 HEADS AND HAVE MOPAR 1.5 ALUMINUM ROLLER ROCKERS THAT CAME WITH THE HEADS WHEN I BOUGHT THEM. DOES ANYONE KNOW IF THEY TAKE A SPECIAL ROCKER. I WOULD LIKE TO GO TO A 1.6 OR 1.7 DUE TO LOW LIFT ON MY SOLID ROLLER CAM. THE CAM IS A DOUG HERBERT 272-275@.50 .620 LIFT. I TRIED A SET OF PROFORM AND THEY DIDNT WORK OF MY 906 HEADED 440. THE ROLLER SIDE SEEMED TO BE TO SHORT AND DIDNT REACH THE VALVE.