We know cams can have a pretty dramatic effect on FE and powerbands. So, we know a regular regrind with decreased duration will likely give us more low rpm power which increases low rpm efficiency which is where most of us spend our time driving.
We also know that high swirl heads decrease the tenancy to ping and knock which allows higher compression ratios. Higher compression ratios increase efficiency as well. David Vizard wrote a nice
technical article on a head porting technique that does just this. His technique works pretty well it seems, but is tuned for high rpm racing engines. With a bit of playing around I think we can alter that to our advantage.
So, the idea is basically to combine the two above ideas. Vaguely similar to Honda's Vtec-e, one of the two intake valves would open up first. This gets air flowing in one side and creates a nice swirl effect. Then, the second valve opens up, but the cam lobe has a shorter duration and lift, so it closes first too. This leaves the first valve still open to keep the high swirl effect going strong. The downsides are that we probably don't get as much swirl as the vtec-e head, and we don't get the high power output of both valves fully opening.
Here is a rough idea of what the cam lobes may look like.
