[David Philips]

In years past when cars were carbureted the trick was to accelerate as fast as possible without getting into low intake manifold vacuum where you would trip power jet enrichment. This was typically around 8 inches of mercury or higher. With a manual transmission you would also shift as early as possible to get smooth running in the successive gear.

The discussions I'm reading here have you revving much too high for optimum mileage just to get to the optimum part of the torque curve.

I used to have an injected Ford 302 V-8 with a 4 speed auto and it would downshift on hill when the vacuum dropped to 8 inches to avoid power enrichment I'm guessing.

I use a Scan Gauge but it does not have a reading that is a good proxy for throttle opening and modern car with drive by wire systems do funny things with throttle openings that are not linear in response to throttle travel.

This is a a good question to explore. My inclination is to install a vacuum gauge, use the 8 inches of mercury floor for maximum throttle and shift as early as possible. Accelerate in this way until you reach your desired cruise speed.