Yes, i do think wide lobe and then trying to keep exhaust valve opening nearer to bottom dead center.
Reversion is a problem with Atkinson style engines.
The 'Miller Cycle' is a variation of the Atkinson cycle where supercharging or turbo-charging at light boost pressures is used to reduce the reversion by keeping the intake manifold plenum at positive pressure.
The son of Mr Miller worked for Ford and was put in charge of Mazda in Japan...first American CEO
He had Mazda build a V6 with twin belt driven superchargers of the Millenia 4 door sedan:
Without some boost an Atkinson cycle engine probably could benefit from some intake manifold runner outlet size...to cylinder head intake port inlet "Port Mismatch" where the "stair-step" created blocks backward pulses running up toward the intake plenum. Manifold runner should be smaller than cyl head intake port opening.
Other thoughts: ...maybe some sodium filled exhaust valves like the 6.1 Hemi has to help out with tolerating high compression ratio?
Seems like the old 427 Ford exhaust valves with sodium fill are near to the correct size and length. Perhaps some Moparts tech heads know of some other sodium filled valves that are close to the right size?
Honda has a list of tricks to improve fuel economy, and the one about gently shot peening the pistons outer diameter skirts to improve oil retention is interesting:
