Agree with AndyF. Do the simple things first. On your carb that is reducing the size of the main jets. I'm guessing you need to remove at least 4 jet sizes, and it will probably end up like 5 or 6.

Don't you dare start messing with air bleeds. That's for fine tuning later and as you have said yours are not screw in, so that makes it much harder to undo any changes. Also if you are not familiar with Holley carbs that's for someone with more experience to attempt.

Get the main jetting right and then you may want to check on the power valve as Andy said. You said you have 9 - 10 inches and the 4.5 would be in the Holley-recommended range, but they're not an absolute. Without the extra richening of the main jets you have now, the power valve might not open soon enough.

R.