copperline, a few question. Is your fuel the same fuel during this whole process? Does the fuel have ethanol added,10%. Are you using a fuel additive, Sta-bil?
I ask because what is happening sounds like either you have a distributor coil to points wire intermittent grounding to the distributor housing or the fuel is contaminated with crap.
Now the rings and valves are sticking because of the fuel additive, Sta-bil, and the degraded government mandated adulterized gasoline. NO compression to even fire off a low compression engine. The rings Are sticking from carbon buildup in the cylinder ring lands. Rather than explaining the ring sealing process for each 4 stroke process I will say the rings load. unload rotate. expand. retract all in 4 movements of the piston.
The valves are another issue but is caused by what I call varnish on the valve stems. And when cold can sieze the valves, bend pushrods or have free movement till it warms up and then becomes a slow acting glue that the valve guides are loaded and begin to slow the sealing process if the spring pressure can not overcome the glueing process caused by the gasoline additives, from the pump, your fuel station.
My personal cure is to hook up an alternative fuel source, clean fresh non methonol gasoline source, and take fuel pump feed hose and plumb into can, place new hose from pump drop into the bottom of fuel can and elevate higher than fuel pump.
I take propane torch the day before and clear the cylinders of excess fuel not the prefered method but works for me, fire protection handy, chemical, co2 and water very handy. Then onto any used plug heat and clear any gasoline saturation with the plug in plug socket without rubber, and heat until there is no more gasoline vapor present. May take 2 or three seconds two or three times to get plug insulator dried out. Check for good non cracked center electrode. Sometimes the cleaning process will break plug center electrode or separate a cracked one further.
Now onto starting , if you get started, great now have a quart of bottle of Marvel Mystery oil. It works. Use straight or mix with gasoline to thin like 2 stroke mix and either spray while engine is throttled up a little or drip into carburetor straight.
DO not be bashful you will use half a quart or more. What it will do is clean out carbon deposits on the pistons, free the rings up, remove contaminates in the ring lands. It may get some heavy valve deposits, carbon, but it will get to the valve stem varnish that are exposed in the combustion chamber and migrate up the valve stems but not likely.
Now instead of Sta-Bil I use Marvels in the fuel tank to clean fuel system from tank to combustion chamber, now I can get the valve stems clean. Using Sta-Bil does work. But I have found to many negative side effects using it. It seems bad for any cast iron made carburetors, causes the air passages to gum up or help promote rust. Turns my carb bowls green. I got tired of constantly breaking down carbs to find green crap in, on the cast iron plugging air bleeds, passages.
Looong post but I hope it helps with the great feedback posted already you will have your truck back in good health.