Lean burn to old style ign swap?

The later 8-pin GM HEI module is better, simpler, and more robust wiring than the 4-pin. Get the parts from a 85-95 V-8 truck. Many posts. TrailBeast sells as a kit if scared of junkyards. You can connect computer spark control (Holley Commander 950, other EFI), then your lean-burn distributor is fine. Otherwise, get an earlier distributor w/ vacuum advance. I don't even know if the lean-burn distributor has mechanical advance, since might have been done inside the "spark computer" box. I think it is also a Hall-effect signal, which may not work w/ an HEI or Mopar module. Both of those are designed for a "variable reluctance" signal (mag pickup).