408 wont run

i had the same problem when i wired a 6al into my car.
i had to wire together two wires so i got 12v to the msd during the start position and the run position of the ign switch.
you could find the two wires at the ballast resistor or you could wire it up right at the bulkhead...which is what i did since the previous owner did some pretty ratty wiring to install an electronic ignition.

find ign1 and ign2 on a wiring schematic...