The engine mounts your going to have to figure out what kind ya want, Read a bunch of posts on this site and decide, there are a few way's, 3 point, 4 point, rail system for those to connect to, There is a poster  named "IronMan" that makes them so look his posts up, That is where I intend to get mine, I also am building a Baja.

Most Jet Boats don't run regular engine water pumps, Our engines power more powerful water pumps (The Jet) that we run water from and through our engines and then usually out the exhaust and/or a side dump and again there are many way's this is done.

I'm sure someone can help ya out more then I but I suggest you just become more familiar with this site and read on, Thats what I did and it helped lots, Welcome and good luck...

Oh yeah and BTW, Pretty much mandatory unsaid rule, Ya gotta post pic's of your boat               Roy

The water supply comes off the pump on the inside of the hull-driver side. Its 1 3/4 pipe, tube, or some kind of apparatus. should be below the hand held cover to the right. I would go with the rail kit to mount your motor. It looks the best, beefy as hell, and makes removing and installing you motor much much more easier.