@ erik,
I don't think it's much use building anything that isn't highly efficient. That means good power with as least waste of fuel and money on not needed parts as possible. I'm not saying that a 600 HP motor can be fed on as little gas as a 200 HP motor can. Mostly things that make engines fuel efficient are the same things that make them go fast, because the fuel efficiency comes from a better burning process and preciser spark and valve event timing (etcetc...), which in turn gives more power. Even Winston Cup engines are designed to be fuel efficient. OK, they might only get 5 mpg at WOT, but with hundreds of HP and loads of torque that certainly is a kind of effiency, considering that many badly built 350s only get 15 mpg and have much less than a third of the power a winston Cup car has.
Quite apart from that, I guess 80% of the users have a couple of questions about timing their dailys, replacing a 305 for a 350 in their pickup, building a tiresmoker that sometimes sees the strip, but should also go to work every day... I'm not denying this is a forum intended for hotrodders. But here are also many people just wanting to learn a few things here and there (like me) without ending up spending 5k on an engine that burns their winter tires to a frazzle in a quarter second. But that's just my opinion, no offence meant.
Greets, Max