I've had all of these symptoms.....the 6AL box checks out, the cap and rotor are new, the box and coil triggers manually, but nothing (no spark) at cranking. Have 11v to the box while cranking and 13.6v when off. No spark or intermittent spark to pugs.....tried all the MSD diagnostics but found something out that
nowhere does MSD talk about.
THE GAP BETWEEN THE MAGNETIC PICKUP AND THE RELUCTOR.
It is possible to install the magnetic pickup too far away from the 8-point reluctor for it to trigger the box. They should tell you to gap it at no more than .025" then set the two cap screws and seal it with some RTV. And don't forget to put a thin coating of machine
oil on the exposed metal parts.....they rust. Fires right up every time now.