No fire at all, just crank and crank. But to answer your questions:
The green wire in the pic does go to the Tach. And the engine ran fine for about 600 miles hooked up that way. I guess what you're getting at though, is that the power to the coil could be grounding through the Tach? Hadn't thought of that. I will disconnect it and see what happens. Keep in mind that the engine ran fine for a long time, then the Tachometer died, then two or three starts later the engine would no longer start. So the lack of spark and the Tach are not perfectly correlated.
The other dark wire you see connecting to the same terminal as the Tach is actually a Red wire and it connects to the distributor. Pretty messed up, and this is on the negative terminal of the coil (distributor wire and tachometer wire). I don't know why the prior owner was into using Red for ground everywhere (the battery ground is also red). Anyway, a coil will function reversed (not as well), but I'll swap things back to the proper locations: negative to distributor and positive gets the lead from the ignition and the tachometer (after the truck runs with the tach disconnected).
I'll try your jumper from battery positive to coil positive tomorrow and let you know what happens. On the spark plug test I was using one of those inline tester gizmos for the spark plug lead, and for the coil lead I was holding the HT wire out of the coil next to the head; touching, close, far away and it produced nothing.
