Assuming all the normal things are in spec like point gap, ign timing, valve settings, etc....i think the only thing you can adjust to minimize hydrocarbon and CO emissions is air/fuel ratio via jet settings. But you need an A/F ratio instrument to do this. Maybe a local garage can assist. Also, there was a vacuum retard to reduce emissions on early 70's cars. Maybe retarding ignition somewhat also reduces HC emissions but not too sure about that.
Dean