I have a single Stern Drive with 454. I cant get my boat up on plane, my WOT is only 3100 rpm. I have trimmed up the motor and used my Trim tabs and still can't get my WOT to 4500 or my boat up on plane. My boat is a 27ft Amber Jack Sea Ray Bravo 1 with a 454 and 4 blade SS prop. Please help. do I need a different prop, different gear ratio? Any Suggestions?

Sounds like it has way too big of a prop. What prop and what pitch??? and what gear ratio outdrive???

you are starting with the tabs and drive all the way down? What pitch is the prop?