timing pointer

I've never seen a rig such as you describe, but the Detroit factories in the mid-to-late '70s fooled around with non-adjustable timing, in response to the smog-nazis in Washington. One factory-service setup used a remote magnetic sensor that snapped into a bracket and read out timing on a display. There was no "timing mark" as such. I suggest you go to a wrecking yard and find virtually any Ford V-8 from '57 to about '73, and either take its timing pointer, or spend 5 minutes to make a copy out of sheet metal. Be sure you index it to TRUE TDC, not just an arbitrary mark on the harmonic balencer. Balencers often slip with age, changing where the mark appears.