With 1600 miles on a 5.4 Screw with 3.55s, got 16 mpg going to work, ect. Next tank, went 220 miles down the highway which includes going thru some small towns, came back and used the rest of the tank for running around, work, etc. Got 18mpg with that tank, so I am satisfied. Full highway should be close to 20. I run 70 mph a good bit of the time.

 

I thought it was 97-octane racing fuel you were talking about. Sunoco sells 100-octane race fuel here in FL but I think it’s leaded.