Will 33x12.50 tires help or hurt gas milage?

[Big-foot]

Hey all, I see a lot of NW posters here. I got this K5 a couple months back, except for the rockers it's in pretty good shape.

The tires will need replacing this year and I was wondering if the extra drag of the 33s will offset the higher gearing, they say $5.00 gas this summer.

It has the 350, 4 speed and 3.07 gears. Even with the 3.07 gears I rarely use 1st and I can get into 4th at 35 MPH if I'm not in a hurry, just feels like it could be geared higher on the street.

I have a set of 31x10.50 mud tires on another set of wheels for off-road so the 33s would only see street use.

Thanks