In my experience the Holley/Weber 5200 is a better carb than the rochester in every way. To me it is cold starting that really shines. If you are used to those long warm ups thast most rochesters require, you will be VERY HAPPY with the H/W 5200. I don't know if you've had problems with a dead spot just off an idle with a rochester B, but all the monojets I've seen had that problem, but the H/W 5200 is very smooth. I think you're going to be happy, but do not expect a big performance gain. You'll see some, but the biggest improvements are cold starting, and all around drivability.
Boo
