[lizziemeister'sV6]

My direction to you is to start with backing down the jets - that carb is overkill on fuel metering when it comes to a 305. Did you check your power valve to see it's not ruptured? Holley's been known to blow their power valve if the engine back-fires thru the carb. What kind of exhaust system do you have? With any engine when you start feeding it more gas - you need to increase the air flow - usually this is done with increased cam lift/duration and timing adjusted to comsume the increased fuel - and then you need to be able to get rid of the increased volume of exhaust. My advice is to get a good flowing exhaust system before you do anything else. What goes in - must come out.