How can I increase the width of the product lookup on quotes in 7.6.2.0?

The product lookup box that return a short list of matches from the product catalog when you start typing a name is too short of our implementation. It's only 162px wide and we need more like 400px. I found numerous suggestions on how to increase the size but none seem to work. 

The css class is yui-ac-bd but I can't find where that is set anywhere in the code and everything I've tried to overwrite it has failed. 

Any help would be appreciated. 

-pat