A worn distributor would not cause a no spark condition. It would show up as rough running or eratic running. There would still be some spark.
Not quite true ...if the rotor shaft of the distributor is not turning then there would be no spark at all.
You indicate the rotor is turning so that won't be the case.
On my 86 C20 with a carb. there is no spark control box or ECU simply a HEI type of ignition. This consists of the coil in cap with a pickup coil and ignition module ( in place of breaker points ).
1 - Check the ohms reading of the coil between the red (BAT / B+ ) and the yellow ( TACH / C- ) should be between 0 and 1 ohm and each one of those to ground should be infinite ohms.
2 - check the ohm reading of the center contact inside the cap to ground ... should be between 6000 and 300000 ohms. Make sure the spring is contacting the coil
3- check the contact strip of the rotor for continuity
4- is the rotor contact swiping the contacts in the cap
5- check the ohms reading of the green and white wires from the pick up coil ... should be a steady 500 to 1500 ohms when flexing the wires.
6- check continuity for the three wires ( brown , black , pink ) coming from the distributor base to the cap.
7 - check for broken teeth of the pole piece ( stationary magnet ) and / or the rotating pick up.