I have an '86 capri 1950 with a 305 chevy (volvo penta) and what I think is an aq250 outdrive or something around those lines

I've replaced the carb already because it had a quadrashit and I thought it was just dumping fuel but anyway I Did an oil change yesterday, ran it for 3 hours today and ended up with 7 quarts of oil in the motor (5.5 oil and the rest fuel; it definitely smells like fuel) Its getting fuel in the crankcase like crazy so I thought fuel pump. Checked it and it looks fine, put fuel in the engine part of the pump (while it was off) and waited 3 hours and the level didn't go down so it didn't leak at all, tried several tests on it so i think its fine.

The motor has a LOT of blowby, I've got clouds of white smoke coming out of the breathers, BUT i still have 122lbs of compression in every cylinder (ranging from 120 to 123)

It revs up perfectly fine when its in neutral but as soon as it has a load it has trouble. It is the correct prop so does anyone have any ideas for either problem?

The fuel issue or the power issue? I can get it up to 2800 to 3000rpm in the water (about 25 to 28 mph) but thats as fast as it will get. Do you think its just a worn out motor and needs a rebuild for it to rev up and run right again?
Thanks!