Are there any disadvantages to this style of SS crossover?

How much HP dose this save, and what kind of speed gain would be involved? Would it be noticable in a 3400 lb boat?

Prob very little or none and no ....

You won't see any difference except for maybe excessive water pressure. Be sure to install a water pressure gauge, even if it's just a temporary one, to verify the pressure.

Hpy is looking to go blown, so a crossover should be used. At the most, you'll gain 10hp. You'll also run into water ballance and temp problems. I can't it in your pic, but the crossover MUST have a bypass. That's the only way you'll ever build heat into your engine.

wow been a while for this question
do a search on water pressure and crossover and enjoy the reading

iam running 540s with no surculating pump, no thurmastat,--i have read meany times that the pump is worth 15hp. runs grate