79 Crew Cab 2 Wheel Dually - Won't Crank by Key (Pics Included)

[bd94s10]

I'm pretty handy when it comes to working on cars and trucks. I'm trying to determine what my next course of action is here. Any help / advice is appreciated.

79 GMC crew cab 2 wheel drive dually I picked up in June has been doing fine. I noticed a starting issue from the day I got it. Every several cranks it wouldn't want to turn over. Keep trying it several times and blam, it would always fire over.

Since June I've done a good bit to the truck but I'll stick to the wiring for this post.

-starter checked and works fine
-ran new positive / negative from the red top Optima Battery (used a positive cable I had sitting from my 94 S-10 and purchased a new negative (which is ran to the starter bolt - which is where the org ground was at when I bought it)
-ran a new ground straps to the frame and cab
-Ran several misc wires such as from the battery to the junction block on the firewall

I moved the truck a few weeks back to work on it and all of a sudden it would not crank. Nothing I did worked. Did some investigating and realized I had a few more challenges. The junction block on the passenger side of the firewall was toast and the smaller cabler going to the starter was nasty so fixed both of those issues. Then proceeded to put on a new ignition switch just for the heck of it. Truck will not start.... so my buddy comes over and starts the truck under the hood w/ my new wiring setup. Truck cranks fine and much better than before.

The issue is no matter what I cannot get it to start from the key. So this past Monday I do more:

-Trace wires from my new junction studs and find a few potential suspect spots
-Cut, solder and re-wire a few small things
-Test light on the fuses and all seems well
-pull the fuse panel apart on the driver side firewall and peak inside and doesn't look too bad (could use some dielectric grease)
-Still nothing

My questions are:

-should i replace the neutral safety switch? or what is the best way to test it?
-what wire on the ignition switch should I look to test?

This truck runs great but... the previous owner did a few weird things w/ the wiring, which is ticking me off.

Pics:

Junction block that was toast



Smaller starter wire was not good



New setup includes 2 junction studs, which replaced the org junction block - please note there is one less wiring going to the right stud because when I put the new battery cable on it had the lead that went right to the back of the alternator. Previously, the owner ran a wire from the back of the alternator to the junction stud so that was eliminated with the re-wire I did.



Main fuse panel, which looked horrible when I first got into it but it has solid connections and dried up dielectric grease



Anyways, I appreciate the help. I'll be posting helping others and showing the progress on the truck. I've done a ton to it thus far including the rear Belltech shackles and hangers, window regulator (drivers side), door pins (driver side), swapped gauges, painted the gauge housing, installed LEDs for the gauges, had the air cleaner sand blasted and powder coated, built a wood housing for the free Alpine my buddy gave me, etc. Here are a few more pics: