Bruce, I think you are right about the rpm. Probably, it wouldn't even have Gen 2 torque levels, with those shorter runners, unless it also had a bigger displacement. The shorter runners extend the torque to a higher rpm level, (because they offer less restriction to the incoming air flow than longer runners) thus resulting in an increased horsepower figure over the same engine with longer runners, like the Gen 1+2 intakes, all other things being equal. But those shorter runners reduce the twisting force at lower rpms, since they have no inertia effect.
Horsepower figures are a mathematically arrived at derivative of torque and rpm in a formula, which escapes me right now. Its all about torque, and the higher the rpm that you can keep up the twisting force of the engine, the higher resulting HP number. HP is really torque, as a function of rpm.
Short runners basically just get out of the way of the air flow, where longer runners give the air a place to rush into and pile up, generating the inertia compression. Too short of a runner offers no inertia effect, except at higher rpms. Too long of a runner may generate both compressions AND rarefractions in waves, netting no useable inrush inertia compression gain, and which may not coincide with intake valve opening, and generating CFM flow robbing turbulance. The tuning of the length of the runner varies from like 17.5" inches on an L98 small block Chevy, (low rpm advantage), to what, like 6" on a trumpet intake like you used to see poking through the hood, on race cars of the 60's? (Netting inertia compression at higher rpms, with minimal restriction).
Ideally, the intake runner length should be infinitely variable through all rpms, with some kind of variable intake runner tube, or some such system. The ZR1 had two butterflies, opening first small runners for low rpms, and then as you mashed the pedal, the second runners opened, allowing greater flow. An ineteresting answer to the runner dilema. If you had infintely variable, rpm sensitive intake length, and added to that variable valve timing, and intake valve throttling, you would not need huge displacement to get the torque and HP of our V10s. Displacement is just the cheapest way to get performance, but in no way represents any pinacle of engineering. Gasoline is more powerful than TNT, in the right proportion with air, and much of the energy of the gas is merely wasted, in current engine technology.
So if you are intent on publishing higher HP figures for your new model, you can fairly easily cast a shorter runner intake, which gives a tuned runner length advantage at higher rpms, and an attractive cosmetic difference from last years' model, generating endless disscussions and "buzz" effect. And to avoid the loss of low rpm torque that those short runners will cause (due to the lack of enough length to generate inertia compression of inlet air at low rpms) , they have to give it more displacement for compensation, which increases low end torque by virtue of the sheer amount of combustion taking place.
If there was a 200 cubic inch engine that made as much torque and HP as your Viper, took up less space, weighed less, made less waste heat, used less gas, would you like it? I'm not sure I would, because I am so conditioned to appreciate huge V8s, and obviously, the V10 Viper.
One argument for currently available mass-produced engine technology is, that metal bearing surfaces last longer in a larger engine, and the large bearings in the engine withstand heat better, than do small engines that rev high, and have high HP numbers. Is this a good argument? I don't know what to say to defend current technology. Uhm, lets see, Its cheap, and simpler to fix, easier to repair than a high tech engine.
There, how did I do?
I know that you already know this stuff, and hope you will excuse me for being gabby.