What is the proceduer for replacing timing chain on my 4.3 chev?

first disconnect the battrey then you have to pull all the brackets and stuff of the front of the engine .Then pull the harmonic ballancer (what the bottem pully is bolted to) you will need a harmonic ballancer puller. then you remove the egg shaped cover over the chain and sprockets you will want to line up the timing dots or lines on the gears by turning the engine over with large screw driver. so when you put the new gears and chain on your timing will be right .then just reverse the prosses to put it back together. Good luck!