I run 3:73 gears with a 700R4 tranny, 350. We get close to 20 MPG on the highway, RPM's less than 2000 at 55 MPH. I ran 3:73 gear in our Nova with a 350/350 RPM's were 2500 on the highway, got 10 MPG

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72 Nova SS sold
75 Corvette
52 Chevy Styleline Coupe