1984 L300 4x4 2lt to 2.6lt engine convert ?

I have canned the previous idea of converting to Diesel power. and will look closely at installing a 2.6lt that runs on unleaded, my questions are as follows
1. what sigma/pajero/ or magna would i need to find a compatable engine [year of manufacture , man or auto] to make it a bolt up install to my 5 speed box ?
2. will i also need to make or bye a body lift kit to fit the larger engine in place of the stock 2lt , and where does one find a body lift kit ?
3. will installing a 2.6 require me to visit the dept of motor reistration vehicle inspection division in Sout Australia [regency park].
4. has anyone here done this type of convetion and thinks it was worth the effort ?
The 1984 L300 4x4 i have suits my purposes perfectly, the body, trim and running gear are all in excellent condition, and i am reluctant to upgrade to delica just to gain a little horspower. we are planning a holiday over to perth early next year and to have a little more power would be just great........... but if all else fails i will stick to the 2lt and hope the wind is going the right way. :)
Mark - South Australia