how much cam with performer rpm heads?

Call Summit, speak to one of their sales reps and they will get you the exact specs for the springs. I have the same heads, and bought them fully assembled, and couldnt use the springs, and later decided to swith to 10 degree locks rather than the 7 degree's that come witht the heads. i am running Comp's XE285, which is a 545 lift, and yes the springs on the heads are good to 600, but what about the spring pressure, and how well it controls the cam. I would suggest get the heads bare, and buy the matching springs for your cam, better fit, and they would be designed for your specific cam.