That's my point. I'm not familiar with every sanctioning body's rules, but I'm pretty sure NASA AI is 9.5 lb to hp, no limit on torque. So if you have two motors, that are similar in weight and make roughly the same HP, then the one with more torque throughout the power band will likely be the better choice. That's pretty much the 3.7 v6 vs. 4.6 3v v8 in a nutshell, I will be very interested to see a dyno comparison though.
Of course your right, if power to weight is fixed by rule, than, all other things being equal, you want the lighter car. But if the only consideration is power/weight, then a motor that makes more torque down low and the same HP up top is "better" (being very, very general here). I never meant to imply that the more powerful motor is better, but that the 3v, at the same power as the v6, will have better torque.
And lastly, which do you think is going to be cheaper to mod: the brand new v6 that has a limited following and two more cams, or the v8 that has been around in its current form for more than a decade? I imagine for the most part it will be pretty similar, slightly cheaper in some cases for the v6, cheaper in some cases for the 3v.
Dan