i had posted some thing last week about this and i i only got a couple of reply, wondering if any one can help, just trying to set cav plates on my 1970 aquacraft hear are the numbers,the numbers are plate lenght 5.5 inch, prop to plate 23 and a eight, v drive to transome 90 and a quater, the strut angle is 8 degrees, the plate only moves up and down 5/16 of an inch but i have to have the plates down to get the boat to stay down the engine is 27 and a half from transome to front of the front plate the motor is a ford fe 390 bored and storked to a 455 12 to 1 and is just over 500 hp and 580 ftlbs 29 gears and have tried 15 gears did the same thing and the prop is from rbr in cali 11.5 x 15 the botom of the boat is not that flat, at the very back it goes up alittle and the motor is set up for drag boat style