A few posters have converted their B blocks to EFI, and commented favorably on engine running improvement, especially when cold. But what have been the gains in overall fuel economy, if any? Old C bodies with cast iron blocks are still a lot of mass to accelerate, and they are not exactly aerodynamic either. The best I've ever gotten has been 14mpg on the freeway at about 50mph, but most of the time it is more like 11-12mpg on both my 65 Fury and 72 Newport. I haven't kept the Newport original, so would not be adverse to converting to EFI, if there was a decent fuel economy gain.