It's not that close in there. I have heard of people going all the way up to .080 gap. Chevy actually ran a .060 gap from the factory for a few years.

The sparkplug gaps are like everything else. The factory sets a compromise spec based on a lot of testing. The gap they give for the stock system gives alright power and long service. You can widen the gap, especially if you put a high energy system on, but you my have to change the plugs more often. The spark likes to jump from sharp edges. Once the sparkplug wears down a little bit, it gets harder for the spark to jump a large gap.