6.0 swap, what gears?

[roscoehd]

I have just started driving my 88 GW after the 6.0 4l80e swap. Wondering what gears others have used? I have 31" tires (they don't measure 31" of course) and 4.10 gears runs a little over 2100 rpms @ 60mph. I was hoping to be around 1900 rpms (better fuel economy). I have a 6.0 and a 5 speed in a 81 Camaro and it runs 1900 @ 60, and gets great mileage (have seen over 21 on a tank) even when beating on it.. not bad for having over 500 hp. just curious what others are running and seeing for mileage?

thanks for the help

[csuengr]

For 31's you need 3.54's or at most 3.73's. Part of your problem is the 4L80E has a bad overdrive ratio.

[j20brett]

3.73 should get you where you want to be. if you dont offroad much, 3.54's

[j20owner]

4L80e is also a power hog, which equals a fuel hog. Takes more power to turn the internals.