Also, while you have it out, I would replace as many engine gaskets as you can. Valve covers, intake gaskets, oil pan gasket, etc. and the rear main seal if you separate the transmission from the engine.
It's cheap insurance against leaks on a 14 year old engine.
And you will need to redo the AC as well. The compressor and lines are different on a V6 versus a V8. So be prepared to reclaim (or just vent) the refrigerant, and install the V8 AC lines and compressor and then have the system vacuumed and recharged when it's all buttoned back together. If you have enough money, I'd replace the lines with new ones, and install a new orifice tube and new drier. Hell, get a new compressor too if you have the cash, especially if it's the original one from 2001. You could bypass the AC for now if money is really tight, but replacing the compressor after the engine is installed will be much more of a pain in the ass, although still do-able.