"Bare-Bones" Slant

The emissions crap is not the killer, its the pathetic timing curve and TDC timing. Evap is fine, Cats are fine, even the EGR is not harmful (if its working correctly, not just the 'holes in the bottom of the intake' design: off at idle, on at part throttle, off at WOT)). So get an earlier distributor, figure out the cam timing hurdle and go to town. Most of the vacuum lines are thermovalve switched for the EGR and evap functions to work only when warmed up. If you have no vacuum leaks, they dont hurt anything. Between model year 82 and 83, my 82 Mazda's vacuum hose count tripled.