hey mate, i have i bit of interest in this one too, i used to work with a guy with an 84' single cab with a 308, but that was the 5 speed box...
i may be wrong but the column shift on falcons and commodores cant handle any extra power, and given a small 4cylinder car has less power than a comodore..... a 5 speed may be the go, and will make driving more fun too!!!!!!!!!!!
my mate at the moment in perth is half way through a holden 253 conversion in his 96' lux 4x4, but because the car is newer he has to run it on gas to meet emissions standards,
if its a 2X4, (it is isn't it) a supra turbo 5 speed or a standard nissan box is a fairly easy conversion, but if it was my choice for a non 4 wd hilux i would go a twin cam SR20T, the engines are out of silvias' and 200sx, my mate has this engine in his datsun 1600 and ran 13.22 at kwinana motorplex on the 8th of march, FAST ENGINES!!!
http://www.ozdat.com/ozdatonline/featurecars/p510.htm
heres the page with the sr20 conversions on my mates car and a few others
good luck n be prepared to spend thousands................... at LEAST!!!!!!!
[ Edited on 10/3/2006 by kevo ]