I am considering a gear swap for my wife's '00 Z from the 273's to 342's.

This car is a daily driver and is used on 1000 mile one way trips so I don't want to get too radical. Just a little more ooomph from a dead stop.

What kind of rpms would I be looking at while driving speeds of 70 to 80 mph in o.d. with an auto trans?

Thanks

 

I have 3.42's, not bad on the highway at all. Here's a gear calculator www.f-body.org/gears/