I'm not sure if this would increase your economy, as the engines which use the intake valve type of Atkinson cycle have about 30% longer power stroke than effective compression stroke. Your engine will have the standard stroke, without the extra length at the bottom for extracting the full energy from the expanding gases. (See my post from 2013) Maybe if you shave the deck to obtain 13:1 compression ratio, AND re cam your intake valves to close when the pistons are 30% of the way up, (or, alternatively, you could have your exhaust valve open for that 30% compression stroke. I'm not sure which is best.) Yes, your intake volume (and power) will be 30% lower, but your compression ratio will be the same as stock, (rather than 30% lower) with a longer power/exhaust stroke. For occasional full power, you could add an electric turbo to turn on when your accelerator pedal is fully depressed, to restore your full intake volume for acceleration needs.