Fastest significant results will come from driving technique above all else. (I assume you've seen the 100+ tips - see the navigation, top of every page).
The downside about a carbureted engine is ... fuel consumption instrumentation is far more difficult. (No
ScanGauge, no
MPGuino, no SuperMID.)
If I were in your shoes, I would attempt to calibrate your fuel tank sender to the highest resolution possible so you can at least track fuel use between fill-ups.
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