Your argument is still flawed. You said that added 4 valves per cylinder on the Hemi would help the fuel economy in a 7.0L version which is an increase from the current sizes as well; therefore, make up your mind. Whether it will improve the economy or not.

Next about the 3.3L to 3.5L argument being displacement, what about the case of the Chrysler Pacifica? In the first generation offerings, they offered the 3.8L OHV (which is just a larger version of the 3.3L OHV) and the 3.5L SOHC with the same transmission and gearing; however, the LARGER 3.8L OHV was rated at getting 25 mpg on the highway, while the SMALLER 3.5L was only rated at 23 mpg. That disproves your argument that the drop in fuel economy was due to a very slight displacement increase as a DEcrease in displacement did not help the 3.5L in getting better fuel economy. While we are looking at this engine family and platrform, why don't we see how the difference in displacement effected the fuel economy between using the 3.3L and 3.8L engines in the normal minivans. The fuel economy on the 3.3L was 26 mpg while the 3.8L's was the same 25 mpg. Over double the displacement increase made less an effect on the fuel economy than shrinking the displacement and using a 4 valve OHC head. Therefore, I find it hard to believe that the displacement is at complete fault of the fuel economy drop, not to mention again that the higher compression ratio would have helped counter that drop or the fact that according to you it should have "helped" the fuel economy.

About the quad fours, that quad 4 that I compared was not even the 180 hp H.O. version, just the 115 hp vs. the 160 hp. Also on top of that, as you reminded me the Neon was unaffected in fuel economy between the more performance tuned version whether it was the original SOHC vs. DOHC H.O. or the SOHC vs. SOHC H.O. therefore, I don't buy that argument either.

As for the Europe issue, take a look at the non-diesel offerings that come from Europe from just about any brand whatsoever, they get terrible fuel economy for their size. Volkswagen is one of the least efficient manufactures on the market for their displacement and technology. I will slam MB with pride as they are a joke when it comes to fuel economy. Take a look at the gearing for those V8 MB models they have a new 7-speed automatic with the top ratio about a .72-.73 with the axle-ratio of 2.65 can only muster 24 with a 5.5L V8 on the S-Class. In contrast the LT1 powered Impala SS got 26 mpg with only a 3.08 axle ratio with a .70 top gear ratio with the old 4L60E 4-speed; therefore, the Mercedes had the advantage of taller gearing, it had the fuel saving advantage of VVT, it had the compression ratio advantage of 10.7 to 1 vs. 10.0 to 1, it had the advantage of a slightly smaller displacement (5.5L to 5.7L), and still GM still won. Before you argue the weight advantage that the Impala SS had, look up the E-Class which is lighter than either example, it only got 23 mpg (which means I was chosing the example that favored MB). Remember that the LT1 was a Corvette spec engine just adjusted for torque over hp in that version. As lear4406, explained there is a 25mpg Hemi powered Chrysler car. The real question is how these cars would compare if Chrysler had an equal transmission offering (a 7-speed auto with 2.65 axle ratio instead of that left over 5-speed MB unit they had to use on the LX cars).

Also, try to find a gas powered V8 sports car that can get a 28mpg that has the displacement of 6 liters or larger in a 3 or 4 valve configuration from Europe. The old tech LS2 managed to do that in the Corvette and I can't find one that can match that. Or how about a 7 liter that gets 26 mpg?

Most likely the reason why they use 4 valve in Europe is more simply that the engines they are using are so darn small that if you offered them in anything other than 4 valve, they would become underpowered. Also just because they care mo