Tow vehicle Question

[Snapspinnr@aol.com]

I am thinking about buying a used 2500 suburban for use as a tow vehicle. 

The only thing that worries me is gas milage. Either my wife or I will have to 
drive it daily and if the mileage is really low it will be a bad move. The 
truck we are looking at a 454. 

Anyone out there have any idea what the gas milage for this setup would be? If 
you have any other insight on this vehicle I would like to hear that as well.

Thanks,

Shawn