Automatic Transmission - Non-lockup converter?

I'm an M6 guy, but I'm buying a Z28 for a daily driver. It has a non-lockup 2800rpm converter. Won't that get worse gas mileage than a regular lock-up converter? I don't know much about these things.

Thanks!

Yes it will provide for less fuel mileage. but, depending on the transmission there is no choice.

What is the powertrain combination?

g

It's a stock '98 Z28 drivetrain, so it's the 4l80E, right?

4l60e is stock