I drive an 84 K5 305 700R4 & 3.73 gears with 33x12.50 Mud & Snow tires. The tire noise at highway speed from the rolling resistance is deafening. My city/highway MPG is 8/11. I want better summer highway MPG. Are there any tires that have street/highway tread in a 33" size? I have replaced plugs, wires. distb cap and carb rebuild. All fuel economy ideas welcome!