IMHO, deck the block to get a 0 deck height. Aluminium heads let you get away with higher compression. Then get a water injection system. You can spray in about 50% water volume as what amount of fuel you are using. So if you use fuel for 20 MPG, you can inject half that amount water in addition. Remember that water injection only comes into play as your manifold pressure rises or said another way, vacuum drops. The water injection should basically come on about the time fuel enrichment also comes into play. So you are not going to use 1/2gallon of dustilled water every 20 miles.
The quench aids turbulence or swirl in the chamber aiding fast combustion. Better power, fuel economy and lower emissions.
If you get the exhaust valves and seats cut for a 40° seat angle you can probably use a single pattern cam of about 220° @ 0.050" lift. I would look for 0.500" lift. To get that you may need higher ratio rockers.
Just my $0.02 for consideration.