1973 f100 360 engine, No Spark

[willys59]

I decided to take out the heater box. Being I don't have a heater or an air conditioner on this truck and the box was blocking the left bank of spark plugs I figured it would make it easier to do a tune up which is what I am about to do. After I got it out, I tried to start it but nothing. I checked and my plugs and no spark. I didn't think there should be any wiring going to my heater that should effect my engine starting or is there a ground I might have disconnected?

 

[willys59]

One thing I noticed also and forgot to tell you , is that when I turned the key to start the truck, instead of my battery gauge showing 13.4 volts, it would go straight to negative voltage. The battery is new and is cranking fine. I have solid state ignition that is pretty old and probably needs to be replaced, so it may have died.

 

[willys59]

Got it.