Get everything that is attached to the engine if possible. Starter,ac,power steering ,ext. Your 4l60 will bolt up but the pins or electronics will be different. Get the trans with the engine if possible, otherwise you can rewire your trans. You can order a stand alone harness or get the one off the doner truck if you feel like you can rearrange it so it works with your truck. I am in the process of converting a 92 silverado this spring. All the info I gave you has been gathered since Thanksgiving this is my first swap and I know there is more to cover but I haven't got there yet.