The only benefit of this conversion is that there are a LOT of tuners who can tune a LS1 type PCM. Very expensive conversion and the tune isn't cheap either. Your better off either learning to tune it yourself by visiting Delcohack or PCMhack as they are known now, they can real time tune the original Delco PCM or they can steer you in the direction of someone who will be able to assist you.
Performance wise there really aren't any gains to be had.
Anything is doable but fitting the hardware to the motor at the very least will be quite a mission (read $$$). Do some research - the delco ecu of those old dears are very configurable and I think you'll find it's up to all but the most wild holden donk.
I looked into it and will be hopefully attacking the task in a few years.
so far what i discovered:
you'll need to add in a crank angle sensor (if you get one of those billet timing case covers there'll be a flat enough landing to mount one. MSD have a kit with a suitable sensor.
I've seen two types of billet timing case cover, the one i liked the best runs a timing belt on the outside instead of a conventional timing chain allowing you to re-degree your cam at will.
Both billet timing case covers require an electric water pump though.
Use the dizzy as a cam angle sensor.
haven't really thought out mounts and coil on plug options but cheaper easier conversions use a dizzy (i'd prefer C.O.P)
Haven't looked much more into it so far but it's an interesting thing to try.
Tuneability of the delphi ecu is excellent vs the already well established tunability of the delco which is quite a damm good ecu to begin with.
I only want to do it sometime in the future so i can add it to my list of things that "I've done" hopefully it wont end up on the other list of things that "i haven't done or failed to do" much like brooke shields!!!