I am thinking about buying a Suburban in the 87?-91 range and have no idea what these get for MPG, reliability, etc... w/ the TBI 350 or TBI 454? Is there that much of a diff in fuel mileage between the big and small block? I would ultimatley like a 90-91 3/4 ton w/ the 454... but it is also going to be my wifes daily driver and I don't really want a 7mpg rig... so I may settle for a 1/2 ton w/ the 350! Sorry if this is a dumb question, but the only chev truck I have ever had is my wheeler...and I never worry much about these issues with that!!