I was just going to post my recent addition. A Q series 750 for my 427w. I tuned it yesterday and it was almost perfect out of the box. I lowered the secondary jet from 84 to 80 and the pv from 4.5 to 6.5. It runs a solid 13" of vacuum at idle and the throttle response is so much better than the Holley 750HP it replaced. The fuel bowl level should be in the middle. You may find that a little higher is better than lower. This should help:
Carb Class: Baseline Setting for your new car