Popping through the carb can also be sign of sticky intake valves. Run a heavy dose of "Sea Foam" additive in the gas for a few tankfuls to try to dissolve any carbon deposits or varnish on the valve stems. Did the truck happen to sit unused for a while with gas in the tank? If so, stale gas can, and usually does form a gummy residue that can stick intake valves to the point of bending pushrods.

Some of the information in the tech article you mentioned can be misleading or downright wrong- - - -research other sources before accepting it as gospel. Stovebolt engine timing is set by a dot on the flywheel and a pointer visible through a window above the starter. Most (but not all) engines time by aligning the dot and pointer with the engine stopped and turning the distributor housing counterclockwise until the points just barely open. (static timing). That's approximately 5 degrees before top dead center.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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