Well, to toss a Berk in, yeah, MAJOR work. Tom will chime in I'm sure, as he's done it prolly a couple hundred times. Don't think you wanna do that. Ain't cheap and not something a novice (as I am) DIY'er normally would attempt.
Personally, I would leave it a Jacuzzi and call it good. PM Chromey and see if he still has the pump.
As far as the 460, well, Dammit! Why do I ALWAYS find all the good chit and deals only to give them all away?

Anyway, I just happen to have bought a running one (Fully marine Hardin 460) about as complete as complete gets, trust me, for a future project. (GT, you have seen the pics, as has OC2).
I kinda, well no kinda about it really, threw it into Glenn's lap for now, (boy is HE happy!) as it's closest to him, so, maybe something can be worked out here on this engine. (All I want, beyond negotiated price, is all the leftover stuff that can help me replace the thing later and a few unique parts from the engine I know are on there! The parts I speak of I have standard replacements for.)
Glenn, you in on this? Lord this better not be like the LAST guy I felt sorry for and never heard from again (Maybe Elwood has though). I better not be getting screwed on this deal! Had enough of that, lol!
Ray
PS, Better get pics of the boat up. Trust me, these guys are relentless on that!