No shit Sherlock! 
Please don't be offended, I couldn't resist. Sorry 
My theory (and the reason for my question) is:
On a 4V headed street driven engine, these short runners will make less torque low and midrange, so it is more useful with a big cam that focuses on the Highend Power.
Big Cams mostly come with a lot of overlap which leads to a lot of reverse flow through the short runners, which the Webers don't like, correct? (this is just hearsay for me, I have very little Weber experience) This would make low and possibly midrange even worse.
So this all leads to a high revving racy application, but if so: why would you care if it fits under the stock screen?
So, I hope there are some flaws in my Theory, otherwise I simply don't get it.