Welcome to the madness-
There are 2 different models of Jacuzzi- WJ and YJ. Which one ya got? There's a tag on the inside of the transom above the front bearing area.(WJ-12-B)
A 4 point mount would work well with a WJ. Dont know about a YJ. Bell is the same for a 350/454, front mounts are different. A WJ and Berk drive line are the same spline count. Sounds like you need a PTO and a drive line or source a rockwell driveline. WJ's will run like a berk, YJ's, I dont know.
Tom @ Jet Boat Performance is always my first call for jet parts. Theres Rex marine, C.P. Performance, Home Depot Speed and Marine, and others, and the classifieds here.
Post some pics of your project.
Daniel