Just a suggestion......get with Tom Langdon (Stovebolt Engine Co.)and get his Holly/Weber 5200 2 bbl carb with adaptor, linkage, and electric choke. I spent countless hours trying to get Rochesters to perform consistantly and the H/W out of the box is like magic. The total cost was less than a rebuilt Rochester and the driveability is awesome.
Do yourself a big favor and check it out. Hope this helps.