Effects of advanced timing on gas mileage

[Hawaii-50]

Under normal driving conditions (80-90 hwy miles daily) with an occasional spirited launch once in awhile, is gas mileage really affected between stock and 14 degrees advanced? I backed mine down to stock when I moved to the outskirts of town, but wanted to bring it back to 13-14 because she feels a little more sluggish than I prefer. I currently get 21 mpg on the highway and yes, I know these cars weren't made with very long legs.

Ted

 

[795.0pacecar]

I've got my timing at 15 degrees and I get 22mpg with a combo of city and highway driving.

 

[Roland69]

Can you tell a difference when advancing the timming.

 

[HISSIN50]

Timing advance wont affect milage noticably. It is kind of like gears in that [theoretically] since you get more pep per pedal effort, you might not need to be as deep in the throttle to accelerate at a given rate. This is purely theory since timing advance is good for so few HP.