Okay, this is for a big block. Does this mean that the advance on a big block once set isn't at 35 but something higher? I guess that is what it means to curve a distributor. If the maximun timing is suppose to be at 35 with a big block too, then I am going to have to add material to the slots to reduce the maximum advance, right? And, oh yeah, this reading is with the vaccum disconnected. With it connected, the maximum timing is out of sight. Maybe this is why my engine has never really been a super great perfomer.