1971mach1

I would address the gas smell first, the gaskets on the Holley could be leaking.

urban_cowboy

Man, I would not use any generalities or fuel economy to determine if you are tuned right. There are just WAY too many variables to even list. I get 13mpg on the highway at 70 turning 3300rpm, but I also burn 1 gallon on even 1/4 mile track run. And that is with a carb that is tuned right. Concentrate on getting your carb tuned correctly with with a dyno tune or a AFR and the mpg will be whatever it is. Gapping you plugs more should help with economy given that you are getting enough voltage to the plug, but it is going to hurt your performance at more full throttle.