new hemi mpg in an Abody?

Variable Cam Timing and MDS are completely different. VCT advances or retards the cam timing in relation to RPMs to maximize power and torque; MDS shuts off fuel, spark, and valve lifters to four of the eight cylinders when cruising to save gas. There might be a way to keep the two (or just MDS on pre-'09 engines) if using the stock engine computer but even without them you'd be pushing around 22-23 MPG on the highway and 17 or so around town. An A-body Mopar would be about the lightest thing you could easily put a new Hemi in, so it should be easier to get good mileage with the correct gearing.