I have an 85 5.0 lx coupe i'm running a MSD 6AL box with a 7000 limiter, so that i can shift at 6500. But my stock igintion box is limiting the engine at 5500 rpm. The coil is wired directly to the MSD box (orange and black), the distributor is wired only to the MSD box(I forgot what color the wires were but it is the duraspark without the trigger wire [white]). The switched ignition wire(red) is routed through a switch in the cab . How is my stock ignition box limiting my engine? Appreciate the help!!!