I have an 84 Runner, I have everything ready to start going back together but I can't get the large sprocket back over the cam. The kit I have is for 85-95 toyotas because the 84 kit I had contained the wrong upper sprocket, wrong by a lot too. The chain that came with this kit just doesn't want to seem to stretch enough for me to get that sucker on. How can I stretch this chain and start getting this thing back together?

Manually depress the tensioner then pull up on the chain/sprocket. It will go, just takes some work.
Dan