Now there are two places you will mark each piston assembly: at the base of the connecting rod, and on the rod cap. You will see a horizontal line connecting the two. You will stamp one number above that line, and one number below that line. That way you will have one number stamped on the base of the connecting rod, and one number stamped on the rod cap. I didn't get a chance to take a pic of this on my LS1, but I did manage to create an example, shown below, from one of my hot rod magazines:
Now even though the above pic is from a different engine, what you'll be looking at on the LS1 will be very similar. Also note in the above pic that they have the number 4 stamped on both the rod cap and the connecting rod.
Now how do you know which piston gets what number? Refer to the GM Service Manual of your engine year (in my case, 1998), or a Haynes manual, and you will see the firing order, which will tell you what cylinder number goes to what cylinder, and that's how you know which number to stamp on what piston rod and cap.
Now to stamp it, just press the numbered end of the stamp against the metal, and strike the end of it with a hammer. I sucked at this. You have to hit it pretty damn hard to make a dent. It's tricky when you don't want to smash your fingers:
Now you need to grab your 9mm socket (along with some muscle) to unbolt the bolts that hold the rod cap(s) and connecting rod(s) together, circled in red in the pic below:
Now you can remove the rod caps and get the pistons out. Be careful to not let the piston(s) slide out and fall onto the floor when you remove a rod cap. Get a friend to put his or her hands underneath the cylinder the piston could fall out of. The hands will serve as a good safety net while the piston scoots its way out of the cylinder.
To get the piston out after you've removed its rod cap and rod bolts from the connecting rod, you get a dowel rod or a breaker bar and set the flat end of the dowel rod/breaker bar on the outer edge of the piston slug. You'll see what I mean when you put the dowel rod/breaker bar down the cylinder and look down the cylinder at the bottom of the piston. You don't want the dowel rod/breaker bar to push the against the body center of the piston. It's better to push against the outer edge of the piston that's got some thickness to it. Here's a picture of my buddy Carl getting a piston out on the LS1:
Notice in the pic above that Carl is pushing with his breaker bar tool, and cupping his other hand underneath the cylinder to catch the piston in case it falls out quickly. I would have helped, but I was too busy taking a picture. ;)
The video below is a great example of how to remove the pistons from a v8 engine. It shows you EXACTLY where to place the dowel rod/breaker bar to push the piston out (in case my description is a little unclear), and is very easy to follow:
When you have all of the pistons out, you should have something that looks like this:
To remove the crankshaft, you first have to unbolt all the main caps. You will use a 15mm socket (use a 15mm deep socket if you have to) on the bolts indicated by green arrows in the pic below, and you will use a 13mm socket on the bolts indicated by white arrows:
In addition to those, there will be main bolts going into the sides of the mains through the block. Be sure to remove those. Then you'll just pull off the main caps (except for the last one at the rear of the engine because you have remove the engine backing plate to get the last main out, which I will soon explain how to do). Make sure to keep them in order in a shallow cardboard box or something similar as you take them off. If they're hard to get off, tap them with a hammer on their sides to try and loosen them some, but be careful not to damage them. Then just pull them off with your hands:
Now to remove the last main, you have to remove the backing plate at the rear of the engine. This is where small hands come in....well....handy, because the space in between the backing plate and the engine stand is minimal. Get one of those small hands a socket wrench with a 10mm socket and undo these bolts:
Once all the bolts were out, the backing plate came off pretty easily. Now just bang on the sides of the last main if you have to loosen it some, and wiggle and work it upward with your hands, and it will come out eventually:
Now all that's left to do is pull the crankshaft! Get a really good grip on it, it's a little heavy and slippery with oil. Once you've got a good grip, just pull it off:
Removing the crank will REALLY make you feel like a gearhead.
Now just remove the main journals, and you're all done:
Now the teardown is complete. Well, unless you have engine mounts on the side. If you do, then no big deal, you'll be able to unbolt those without any problems if you've gotten this far!
And just for kicks, I thought I'd include a video that very clearly shows you how the crankshaft, pistons, lifters, pushrods, rocker arms, valves, and camshaft all work together. It's a very clean animation and props to whoever made it. Enjoy: