This is my first time working with a Holley carb. I have a 750 vacuum secondary 4160 on a 509 bbc in a whitewater jet boat. I am making about 400-450 hp at 4400 rpm depending on what impeller chart you look at. I ran the motor at about 3300 rpm (just above cruising rpm) for 45 seconds and shut it off as soon as it went down to idle. How much of a jet change should I make.