Boreing out the throttle body?

[yewknowit]

What will this do for the engine?

[bgreganti]

It will increase air flow and thus horsepower, however I wouldn't expect more than 1-2 horsepower.

Also, you can't just bore it out. You have to make a new butterfly to fill up the new larger opening. Some people have bored out just the ends of the TB and left the butterfly opening the same size, however this will not produce hardly any horsepower since the hole is still restricted at the butterfly.