Aaron,
I would stay with the 351 as opposed to the 5.0 302. It is basically the same engine and you get alot more potential with the 351.
Now you can get a nice turnkey engine from Engine Factory
http://www.fordcobraengines.com/Cobrakitpack.html
I highly recommend them.
You can buy a short block from them also (that's what I did) and build it up yourself.
Or you can buy a block and have it worked locally.
I prefer a carbed engine over fuel injection. I find it less touchy and easy to tune.
By the way, I have a 1974 351W block, crank and timing cover available if you are interested.
Roscoe