kid's 1986 El Camino

Hello all, this is my first post but you'll probably be seeing quite a bit of me. Here is my story, I have an 1986 El Camino that I purchased in 2002 when my first car ('82 prelude) died. I bought it from a used car dealer in Huntsville, AL. I've been in love with it ever since I saw it, but it started going caput on me around March of '04.
Come to find out all it needed was a cam and new lifters, but it has a 305 in it and I wanted to go ahead and put a 350 in it. I started driving my family's old vehicle (mazda mpv) and was busy with my second semester of college so I forgot about the camino. Now I've just been in a wreck (not my fault) and will possiblly be getting about $4,000 in insurance money. I have just gotten permission from my family to put a new motor in the El Camino instead of buying a newer vehicle (I'm 19 by the way).
I am looking to spend at most $2000 on the Camino, which will include a motor and new weather stripping. I would like to add a spray in bedliner and bed cover as the money rolls in. I don't want to buy a rebuilt engine because of the lack of a decent warranty so crate is the route I am looking to take. I'm not familiar with what parts can be put from a 305 to a 350. I have everything for the 305 so what is the smallest "kit" I should buy? Also what will make it an efficient 350, I'm looking for as close to 20mpg as possible.

Thanks in advance for all of your help
-Clayton

sorry.. double post... edited out

There is no gas efficient 350. Either get over it, or get it.
Its the price of having fun!!!