Depending on the use, making sure the jetting is dialed in maybe all you need to do. I've seen that 14.7:1 A/F ratio leaves power on the table, 12.5-13:1 is typically a good performance tune. Unless your really opening up the heads and intake ports and turning high rpm's with a larger displacement build, I'd dare to say the stock carburetor will carry you a ways. What is the engine going to be used for?