1972 SRV180 dragging transom

We have a beautiful 1972 SRV 180 with a 165hp I/O. Even with a full tank of gas in the bow, and two people standing as far forward as possible, the bow rises like a @$@#$ out of the hole, and then porpoises on flat seas. The prop is trimmed in 100%. Does anyone have any advice or experience with such a thing? We've added an after-market hydrofoil, which has helped, but I can't understand why Sea Ray would release a boat that acted like this. I've seen others with this same hull with a 115hp, so maybe the engine is on the heavy side, but even the original manual offered the 165hp. Any thoughts are greatly appreciated.

Though trimmed all the way in, the trim limit switch may be out of adjustment or broken, stopping it from trimming down (in) as far as it should be.
Not sure what the exact adjustment should be for that drive but the prop shaft should be slightly beyond parallel with the bottom of the hull in the fully down (in) position.

What kind of condition is the prop,is it the correct prop,is this a new problem with the boat or is this a new boat to you?

Water logged

Put it on the trailer, trim the outdrive all the way down, and post a picture of it. Someone will tell you if there's a trim issue or not. Good luck.

If its really trimmed all the way down/forward, it will force the bow down and you will not porpoise. Thats a given. If the bow raises really high its even more obvious that the drive is way back, or high. The limit switch slipped or is faulty. You will have to examine it on the trailer.