Good question. Ford continually gets beat up over the fact that their "sports car" engine is a little 5.0 (or 5.2) while GM and Mopar still use what are basically truck engines for their sports cars. It naturally follows that the Mustang is a better road course car than the Camaro or Challenger while suffering in around-town-seat-of-the-pants acceleration and drag racing where the bigger engines are really hard to beat. It's impressive that a "little" 5.0 can even compete. A quad cam, four valve, 7.0-ish sized engine would definitely quiet the competition.
However, the 7.3 concept revolves around the reduced complexity of a single cam and 2 valves per cylinder. Why make the customer pay for the added complexity of a"cammer" engine, and the "customer" here would be a corporation interested in buying a FLEET of vehicles, when the high rpm's where all the cams and valves really make a difference are just not going to be useful.
Furthermore, GM and Mopar have already proven that an old-school pushrod V8 developed with the technology of today can be a REALLY hard act to follow.
I recall talking about this very topic with a friend who used to be a dynamics engineer for Jeep. He said that Jeep and Dodge spent a significant amount of time investigating overhead cams and multiple valves per cylinder for their 4x4's. Their determination was that there was just something about the pushrod engines that made them produce better low end torque which, for the purposes of a relatively heavy 4x4 (Jeeps, trucks, Broncos, etc), made them a better choice.
I'm secretly hoping that Ford will put the 7.3 in the F150. Think back to the 60's and 70's when you could get a 390 in an F100. As discussed, a 5.0 is a poor truck engine...and the F150 is a truck that's expected to haul loads and tow things. The twin turbo V6 is rated to haul and tow more than the 5.0 (with the turbos making the V6 think it's a big V8). A 7.3 would fix this situation and make the F150 the hands-down towing and hauling leader in the 1/2 ton truck category. Sadly, I doubt it's going to happen. Instead, the latest in automatic transmissions, trending toward a much wider ratio spread and many ratios, could overcome the poor low end of the 5.0.
