Vacuum Advance - Carb vs Manifold

Carb and manifold vacuum sources

Vacuum solenoid and conenctions to distributor and vacuum gauge

Range of movement of throttle pointer - no throttle to full throttle

Steady 20 mph on the flat, 3rd gear

Steady 25 mph

Steady 30 mph. To all intents and purposes at any higher speed or wider throttle opening the two readings are the same, just lower