for fuel economy you can't beat a vacuum gauge mounted where you can see it while driving
keep the needle above 10 inches of mercury for cruising
you will not win the stop light Grand Prix but you will get the best mileage you can get
If you need more power(don't we all) run it a between 2 and 6 inches of mercury(Hg)= Power comes up and economy goes down
just keep out of the no vacuum zone<2"Hg or wide open throttle

hank
If I can't fix it I'll F*ck it up so badly nobody else will be able to fix it either