t-400 and gas mileage?

[fast eddie]

just got back from the track about a 100 miles from my house mostly highway miles but bumper to bumper traffic going home averaged 20 miles per gallon with the 400 running about 70 on the highway at about 2950 rpms so much for bad gas mileage with a t-400


ran my best times ever 13.28@104.3 with poor 60' of 2.17
(need some et-streets)

93 oct in the tank no race gas,20# boost