Re: hydraulic jack plate
It gives you the possibility of fine-adjusting engine installation height on transom while running.
In speeds above 50 knots, that might give some advantage.
Lift the engine, less drag, higher speed.
Never run with lift without having a water pressure gauge installed. You may run the risk of lifting too high.
It is not just to install and run, prop tests, cooling tests etc have to be done as well to obtain the optimum result and maximum engine safety.