I'm all jacked up! I'd have guessed a tighter lsa (all else semi-equal) would have helped top end at the expense of low end. That's why i let people smarter than me figure that stuff out!
You'd think considering how rough it can make a car sound. Make's it seem like a screamer. But it's the opposite. Tighter LSA closes the intake sooner. Creating higher cylinder pressure. That's where the more power comes in, along with the lower rpm. The valves opening and closing so soon to each other is what makes the narrower power band. As far as I understand it.
Basic rule of thumb - tight lsa = natural aspirated. Wide lsa = boosted application.
Wider LSA's are usually used in supercharged applications. Lets you force more air into the cylinder because the intake isn't open while the exhaust is, or for not as long anyways. On a supercharged setup, the sooner you can close that exhaust after the intake opens, the better for building more boost. Otherwise you just shove it out the exhaust.