Gas millage????? WTH is that. 97 Silverado, about 10 MPG, 79 Corvette about 8 MPG. Both have 373 gears. Truck has a 4L60E, Vette has the OE 4 speed manual. This is in town of course, and well I do kind of have a lead foot. Both have a 350. L-31 in the truck, and L82, 4 bolt main in the Vette.