Have a FULL model and serial number of the truck?
Just from what youve posted it sounds like the points or module in the distributor that has the wire going to the coil...sound like bad points/module...will,have to take cap and rotor out to check it,shouldnt be no need to remove whole distributor,you already said rotor is turning when cranking.....if is a points setup is a good posibillity they just need adlusted..not opening/closing