..on what is essentially a rag & stick sailor's forum.
Please forgive them & I'll tell teacher not to give them too much detention this evening!
Now your "list"
Is this whilst accelerating and then it eventually straightens up once you reach a level speed? If so it is just the torque of the propellor turning the boat back in the opposite direction and is just a consequence of the physics of a high performance single screw boat.
On the other hand if it remains listed at constant speed, on the plane then I reckon that you have a serious problem with your sterndrive (I assume that it is a sterndrive set-up?) Sometimes one of the tilt pivots breaks or the pin drifts out and although it seems perfectly OK at rest - because the rubber gland is holding it in place - the leg goes out of alignment once the power is applied. I needn't tell you how potentially dangerous this is and that it needs urgent attention. An outboard would suffer similarly if one of the powerhead to stern bracket rubber bonded joints were to fail but you'd see it from the cockpit because the outboard would be visibly tilted over to one side. With either you see, the anti-cavitation plate takes over deciding verticality once most of the hull is clear of the water on high power boats. On racing boats this plate is small so that the hull does the job but as we put higher and higher power "standard" drives on "sports" hulls the cav plate is boss so if it is not vertical because of a mounting failure then neither will you boat be.
Both of the above are speculations as unless it's lying here on the floor in front of one, it is almost impossible to be more accurate.
It may be that your upside down sharks fin anode, the one directly above your prop is out of alignment , had the same problem years ago on an 150 hp outboard on a 16 foot speed boat the faster we went the further we lent over ,straightened it up and all was fine
Could be anything from the following, you have moved some weight, the hull is distorted, trim tab jammed or surface distorted, O/D leg fault . This assumes the condition is constant regardless os side winds ect. Do you have tabs if so which make, which O/D do you have and do you keep the boat on a trailer ?