I've been getting 22 mpg with mostly freeway driving. What can I do to improve that?

I get 22-24MPG in Houston traffic and 27-29MPG on the highway. Here is the receipe I used on my '66 B18, M40:

Adjust the valves.

Adjust the timing by ear for fastest idle and back off just a tiny bit; so you just detect a change in the cadence of the engine.

Adjust and balance the carbs.

Go for a drive, preferrably on a route with a steep grade. Listen for pinging. If necessary, adjust the timing back until it just does not ping on the steepest grade you can find.

Always use mid-grade fuel. I tried premium with no improvement. But, when I tried regular the mileage dropped off significantly. Enough to pay for the difference in cost per tank between regular and mid-grade.

Slow down. The difference in MPG between 60MPH and 75MPH is staggering. At 62MPH I get repeated results of 27-29MPG. Just one trip at 75MPH convinced me not to do it again; the mileage on that trip was 20MPG. An overdrive would help here of course. And, your mileage may vary. :-)

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Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 52 year old fat man