Engine for 620

I am searching for an engine for my 620. I am wanting to put something fuel injected, and half way decent on gas, not to mention something that won't take too much work to shoehorn in.
Can anyone help me out? I am "researching" right now cause I have about a month left before I get out of Iraq, and back home to try to get the damn truck on the road. Hoping to find the engine, tranny, and the rest for a decent price.
Hopefully I can get it all, and get it in within the first couple of weeks that I am back and get to the damn thing before I get shipped off again.
Thanks in advance.

nissan 240x... find a wreaked one in a junk yard, they run really well.. and are actually fast and gas saver at that.... get the computer when u switch motors tho...