Destroking an Engine

To the OP - the right package, matched to the right transmission, will be the best in terms of economy. If you look at the modern cars they are all coming with 6,7,8, even 9 speed transmissions. That's to be able to keep the engine in it's most efficient rpm range more fo the time, rather than for a little time during the rpm ranges of 3 gears. As was mentioned - there are advantages to a shorter stroke and shorter rod ratio. Most being friction but burn time and reduced pumping losses also come to mind. The trick about rpm is no matter how big or small the engine, the more "bangs" you have in a minute, the more power will get to the tires. Period. That's why high rpm engines always make big numbrs assuming they are built to live up there.