I don't have your Speed-RPM numbers requested and wouldn't know how to begain doing the math and wind resistance. But may have something somewhat helpful. I have 295/35/19 Michelin's on back that's 27.1 inches tall. SRT-6 in overdrive with a 307 gear at 2000 RPM's I'm doing 61 MPH. Same RPM with a 327 gear gives me 58 MPH. Then at 2500 RPM's with a 307 gear gives me 79 MPH. Same RPM with 327 gear gives me 72 MPH. Rob has my car so I can't help futher with numbers at this time. Squirrel Crusher