On this engine, I believe the distributor is driven by the oil pump, so a broken timing chain wouldn't stop it from turning. But there are other internal issues that could.
If you haven't already done so make sure the rotor is actually turning. I'm assuming you've actually tested for spark and found none, as opposed to having just ruled out fuel and compression? If you just ruled out fuel and compression, you need to check to see if spark is being generated; if it is, you need to set the base timing by the taking out the #1 plug method.
If you do indeed have no spark being generated and have replaced the whole distributor assemby, ignition module and all, I'd say you should get a multimeter and check for power at the ignition module and check for resistance at the coil and make sure all the electrical connections and wiring between the module and the coil.