MSD firing issue
 

Have been trying to trouble shoot an issue with a new install of my 78 SC 3.0. I have the MSD 6AL digital ignition control #6425. It will spark once when key is turned on then no spark. I have checked the power and ground both appear to be good. Has anyone else experienced this specific issue? If so how did you resolve this? I have checked the wiring with two separate MSD units and they both do the same thing. Motor fires up and runs fine when the Bosch CDI is reconnected.
Also any recommendations where to get distributor re-curved? Thanks Pelicans.

how do you know and what do you mean by it sparks once?

does not matter, you need to flip the wires from the dist going to the MSD.
what I did was ordered a new connector and flipped them there, that way I can still plug in a bosch and it works.

I am talking about the center conductor and shield.

Green and purple from MSD were swapped and apparently no difference.

If hold the coil wire near a ground and turn the motor over it will spark once.

How are you powering the MSD? I ran a dedicated 12 ga wire with fusible link to the battery terminal of the starter motor.
The wiring harness for your CDI may have some sort of override for a not running condition that shuts off fuel pump or other safety reason that the MSD does not recognize.

that is the specific install direction from MSD so if that was not followed all bets are off.

Bingo.