you need,
pedalbox
manual transmission (buick pattern not chev pattern)
dash shifter surround
tailshaft
transmission support
clutch
spigot or pilot bearing (goes in crank to support input shaft, **** easy to fit, not so to remove

only manuals have them)
flywheel
make sure you get the 8 bolt and not the 6 bolt, (vn s1 = 6 bolt, vn s2 = 8 bolt)
if your thermostat hose is at the front you have a series2, thermostat at the back its a s1
ECU is fine because vn/vp used a kickdown cable insted of ECU controlled gear selection..
That should sort you out
if you look hard enough on ebay you can usually get everything you need for $600-700...
Like this but for a VN insted of a VL
Holden VL 6cyl non turbo 5 sp manual conversion - eBay Manual Transmission, Transmission, Car Parts, Accessories, Cars, Bikes, Boats. (end time 07-Feb-09 13:14:47 AEDST)