This is probably a stupid question and i'm not sure if I'm in the right forum. I'm looking at buying a XR8 AU ute. It's cheap with 350,000 km on the clock. If I have to replace the engine at any stage I'd probably look at replacing it with an XR6 engine is this possible? How much work would be involved?

I really wanted an XR6 AU ute but I can't find one where I live and this XR8 is cheap.

Not easy at all. To start with youll be replacing the trans aswell. Add in a suited ECU and loom too. If its smartshield AU, from memory, youll be taking it to ford to learn the new ECU to the BEM also. Might not have to, only 99% on that last one.

In short, buy what you want from the start.
And also, I have an au3 xr8 ute with 250k, and I flog its a*** off every day and have done for 3 years, and the 302 is still chugging along fine apart from some leaks. Awesome donk, and awesome car.

I agree, it's too much of a hassle. I wouldn't even attempt this myself, unless it partly a hobby project or something of that nature.