If they were my engines, I'd get them back, inventory the parts. See what water
damage there is. If you have mostly complete engines they can be rebuilt. The engines probably turned the same way and the rotation changed in the transmission
. If so, it doesn't matter what crank goes in what engine. But if the parts are separate, keep them separate. Everything will have to be mic'd. Once you know what you have, an engine kit with the right bearings, sleeves, etc can be made up. I second PC Industries, but there a lot of good places to get Detroit kits. Including Detroit. If there's a Detroit dealer near, my guess is 10-15,000us each to rebuild
if you pickup and deliver.
I rebuilt my first Detroit a long time ago with just a service
manual and a guy I could call on the radio
. But I had done gas engines.
I have a service
manual on V-71 engines. If you don't have one, I can mail it to you and you can mail it back. It's beat up so no big deal. But from what I've seen of Australian shipping
costs, it may be cheaper to buy one from Detroit. Also if you join https://boatdiesel.com
($25us) they have many manuals
in PDF that can be downloaded.