I'm not really sure why you have a muscle car and you care about gas mileage, other than making sure you reach your destination without incident. I understand the curiosity factor.
Its good info to know and certainly an important part of understanding the machine. But honestly I'm much more concerned with horsepower and torque and whatever gas cost is involved. I don't want to waste gas unnecessarily and I want the car running correctly but I don't think you are commuting to work in this car? And if you are by the way... that is awesome... but you made poor economic choice so deal with it. Yes it cost money to go on a road trip. Stop swapping out the 350 2bls if its such an issue! :-)