I use the Comp Pro Magnum Rockers on a 440 with
COMP Cams XE 284 cam
COMP Cams P/N #911-16 Single Outer Valve Spring; 1.524" (with Damper)
COMP Cams P/N #867-16 Pro Magnum Hydraulic Lifters
Going on 5 years Street/Strip no problems, no complaints but I believe that the springs are considered marginal for my application.