The 1970-1972 Datsun 240z distributor was a single points distributor. The 1973 Datsun 240z distributor used 2 sets of points. The 1974 Datsun 260z used pick up coils and an external transistor Ignition Control Unit. The Manual Transmission models used a single pick up coil and the Automatic Transmission used dual pick up coils. The 1975-1978 Datsun 280z California model had a single pick up coil and the Non California model had dual pick up coils. The External Transistor Control Unit was redesigned, there was a California model and a Non-California model. I also noticed the 1978 vacuum advance controller looked different. Datsun redesigned the distributor for the 1979-1983 Datsun 280ZX, replacing the External Transistor Ignition Control Unit with an Integrated Circuit Ignition Control Unit. This is the Distributor you want to upgrade your Datsun 240Z 260Z 280Z, please check out Ignition Circuit upgrade to Datsun 280ZX IC Distributor for 240Z 260Z 280Z Page. The 1982-1983 Datsun 280ZX Turbo model featured a redesigned distributor, the pick up coil was replaced with a crank angle sensor.
The distributors had different models for different regions, transmissions, and emission control. They also had different timing curves. The Datsun 280ZX Turbo model was completely redesigned. The Pick Up Coils, Vacuum Controller and IC ignition unit were removed. Im a Datsun 240z guy, but I think the new design used the Crank Angle Sensor to deliver the ignition spark precisely. There is no timing info in the FSM, so Im assuming the control unit adjusts the timing. Not sure, any info guys?
Below is a table I made from the Factory Service Manuals with the specs. I found it interesting to see the different timing and timing advance data for the different regions, transmissions, and emission controls. I have also included images of each distributor.