[Dan in Pasadena]

The guy who put in my 6.0 only uses the truck engines - which are cast iron blocs as they are dramatically cheaper and provide the same power as the aluminum block with only a relatively asoll amount of additional weight.

On his Corvette with 6.0 he has driven to Speedweek in Utah from SoCal and gotten 23-25mpg - and he keep his foot in it pretty good. I can only hope I get over 20mpg when mine's up and running.