Hi and welcome to just answer Dodge. Well it looks as though you have eliminated most of the usual things. I have seen this before on the 318 & 360 engines. What I have found is coolant leaking into the cylinder while the engine is off. The next time you start it it misses until the coolant is out of the combustion chamber. One way to check this is to remove The # XXXXX spark plug, disconnect the coil wire and crank the engine over. Look for signs of coolant coming out of the spark plug hole. If you have a cooling system pressure tester, pump up the cooling system and leave it on overnight. If there is coolant leaking into the cylinder this will help force it in there and confirm your diagnosis. I know you said there is no spark, but maybe coolant on the plugs electrode is affecting the secondary voltage some how and tripping up the timing light. Check this and get back to me.
That coolant is going somewhere. You probably don't see it out of the tail pipe because it is such a small amount. Let me know what you find.
Well what you should do is to pull the head and take it to a machine shop where they can check it for cracks. If the truck has a lot of miles, It might be wise to pull both heads and have the machine shop do a valve job. And buy an upper end gasket set. I think if I click on my "answer" button you should get an accept button. Let me know if you don't.
Also let me know if you have any more questions Luke,
Sounds good Luke. Glad to be able to help, and if you need any more info let me know. Thanks for the feedback!