I would swap the carb for a 750 vacuum secondary Holley type, preferably with a metering plate on the secondaries. It will be substantially easier to tune it that way. Get the spring kit for the secondaries and a jet kit with 1 of every set.
That's a healthy cam for 355 cubes and you have pretty good heads. It will want to run with a converter higher than what you have now. I'd rock a 4k converter with a set of 3.73's and a 26 or 27" tire.