I know that a turbocharged engine has the potential to be more fuel efficient than an equally spec'ed N/A engine. Is that something that is easily done?

I've got a late 70's low compression 440 in my 80 Ramcharger (3.23 gears) and was wondering if there was any feasibility to adding a turbo (without any internal engine mods) and seeing an increase in highway economy.

Point me in the right direction if you will