RPM range 5.7

[racerkyle]

I have 1996 GMC z-71 with 5.7 Vortec engine. I'm changing gears becuase of the lift and 35 inch tires under it. I have been told to buy 4.56 gears. They say that will put me back to stock running rpms and I will have an overdrive I can use. What rpm should I be running at 55 mph in overdrive with it in lock up? I'm thinking around 1800 to 1900. need the best mpg.

[jnperin]

You will get the best mileage when you are cruising at the top of the torque scale. I guess you have to find out at what RPM's you hit the top of your torgue

[ManyCamaroz]

You can go to WWW.camaroz28.com and find a nifty little gear ratio/rpm calculator.