Chevrolet Repair: 2005 malibu classic engine change out

Question
How hard is it to swap out an engine? I have a 2005 chevy Malibu classic and have a parts car that is 2004 chevy Malibu classic. Can I just leave the transmission on the engine and swap it as well? How hard is this project? Any advice? Thanks in advance.

Answer
My advice to you is be prepared to only use the main components, meaning the bare block with pistons and heads (essentially a long block)and the bare transmission. You should do the research to be sure the blocks are the same and same with the transmission. Automakers have this thing about leaving things alone these days, and though it isn't likely, it would not surprise me at all if something fundamental about the engine has been changed. A few years back I did this procedure you're debating, on a 97' Caddy Eldorado swap with a '99 same model. They were exact twins, or so it appeared. After I had the engines out and on their stands(use at least one stand)I noticed the crankshaft position sensor was built a bit different and the fastening points were a bit different. To make a long story short, it turned out that internally almost everything was different and not interchangeable. The crank and even the block inside. I have also come across this with the Buick 3.8 l v6, where this one was noticeable as the blocks were a little different. But both were 3.8l Buick v6es from consecutive years. One would think this wouldn't be, but it's true and is something to be sure to avoid. Don't just roll the dice here. Like I said earlier ,chances are this will not be the case. That being said, the proper approach is to use absolutely everything from your old engine ,everything. Take your time, take pictures with a good camera, and flood your work area with an overabundance of illumination. Constantly be on the clean patrol. Spill anything ,stop and wipe it up thoroughly and immediately. Constantly keep at your tool organization. If you find yourself skipping these steps, stop and take a breather and get back at it when you can follow these simple rules. Trust me. A good system of marking all hose and electrical connections and routing and sequence of routing is essential. What I do is start with some good masking tape and a good permanent marker and number lengths of tape and attach it to the part to be noted. On a piece of binder paper duplicate the number and follow it with pertinent information to be sure it goes back in place properly. This will sometimes have to include highlighted notes to be sure you do it in the right sequence, because when reassembling you will be just tackling, reattaching components, checking off your list and removing tape, However, this process will inevitably get you out of the numbered sequence, so it is important to highlight notes where sequence is paramount. When there are no more numbers with notes to check off your list, you can be assured that you have done everything right. That's important. You may get it right not following this procedure, but say the engine will not idle,then you have problems because you cant confirm anything and all of a sudden your day got a lot worse. Adhere to what i said and you have a good chance of this working out for you. Good luck.