Is the distributor shaft turning when you crank the engine? It's a remote possibility, but I've seen sudden timing gear failures that stop the distributor from turning, which also kills the spark. You can open and close the points manually and get a spark, but if the distributor cam doesn't rotate, you'll get neither spark, nor valve operation. That usually happens with a fiber timing gear, if the engine was originally installed in a car. Trucks usually got a metal gear for more durability under heavy duty use.

It's definitely something to check, before you keep chasing electrical gremlins that aren't there!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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