Engine Clanking LA 360 Motor

Take a compression reading on it. Look at the plugs as you pull them. One should be low on pressure. Pull the dipstick. If it has spun a bearing the oil will have metal in it (looks llike metal flake in paint). If it is a rod, you can tear into it and totally fix it, or buy another one and drop it in. As far as crate rebuilders, there are none I trust.