Need Gen III Timing Help

Does anyone know what the initial timing should be on a 6.1 carbureted Gen III with MSD ignition? I don't know whether to time it around 20 degrees or go to the upper 20s. It has a small Comp Cam street cam. On initial startup of about 15-20 seconds running time, the engine was idling around 2,200 rpm. I don't know if the timing is causing it to idle that fast. Thanks for any help!