installing water pickups?
 

How do you mount the pickups on the back of the boat for seawater for the motors? I know there has to be a correct height. The boat is 99 382 fastech. I just dont want to screw this up.

I would start with the leading edge of the PU flush with the bottom of the hull and the trailing edge about 1/8" below the bottom...PU is on an angle. You then file down the trailing edge as needed until you get the water pressure you want.
Depending on the style PU you use, you can drill the transom and mount it so you have about .5" below the bottom then mark and trim to fit.

What he said + mount them as close to center as possible so as not to disturb the water going to props.