1989 Ford F250 7.5L 460ci 2WD Auto.

My grandpa bought new in ‘89, he passed in 2001 and she was used very little and parked in 2010. Long story short 2 months ago I had her towed home so I could fix her up. So she’ll crank fast but won’t fire up every time. I’m getting good fuel pressure, I replaced in tank pump, fuel tank, in line filter and pump on the frame rail, also the fuel pressure regulator. Along with the ICM, coil, cap and rotor, plugs and wires, map sensor and cleaned the IACV. Also new is the temp sensor and air charge sensor. I noticed the spark was weak, yellowish. Could it be something in the distributor? It’s not original but it’s definitely 15+ years old. I’m racking my brain trying to figure this out, I’m not so good with the electrical side of things. I’ve been trying to figure out how to test that I’m getting good power from coil to dizzy, etc.. Any help or thoughts world be very appreciated!