I can add 6mpg & 10mpg with an extra 150hp to V8 gas Ford, Chevy & Chrysler vehicles with factory warranty continuance. Large Family Highway Hybrids with Towing capability. GenesVettes.com. Reduce gas consumption from 30% to 50%.I have 3 test vehicles that I give test drives by appointment.2007 Corvette 34mpg hwy-43mpg around town 750hp-2008 Coevette 32mpg hwy 40 around town 775hp-2009 Silverado 28mpg hwy-32 around town -18mpg towing 6,000 lbs -500hp-550tq