RLSH700 I just enjoy the conversation. Just to make it clear I am not pitching for any one thing in particular. I agree with you on most points except usually with the supercharger or turbo you are using less gearing due to the big torque increase under boost. My old 1987 Grand National used a 3.42 axle ratio and it performed the best with it. I had a vortech supercharged 1993 Mustang with a 302 and it was geared at a 3.55. My Cobra is also a 3.55 gear. Looking at the physics of it, 400hp is 400hp. It will take the same amount of fuel to produce it no matter how many cylinders you have. This being said a 4cyl turbo and a V8 NA both making the same power will use the same amount of fuel at full throttle. The difference is when you are at cruising speed the smaller engine will then show an advantage in fuel economy as it will be out of boost. I've been highlighting the boost thing but let's look at NA. The advantages I like about big inch NA is you don't stress the engine as much and it usually has a more linear curve. What you stated about gearing on this type of set up is true, you won't need as much compared to a smaller NA engine which will help in the fuel economy dept. I will give GM credit as far as fuel economy goes, the LS engines do get excellent fuel economy for their displacement and power. Again, your statements about the Corvette are very true. The LS-7 makes 505hp and is rated at 24-25mpg on the highway out of 427 inches. The 3100pd weight helps though. I have driven a modified 5.7 here in a Magnum and that car performed outstanding. I don't see any Challenger fan being disappointed with the performance of these cars. Thanks for your view points also.