The cam timing is not adjustable without a vernier pulley. Have you got one?

It won't be the cam timing that is making it idle too fast. It needs air/fuel in order to run and something is letting air in which is allowing it to idle so fast. I don't know why you removed the throttle body and inlet manifold as this is not necessary, but if these aren't sealed up properly that could cause this problem.

Have you looked at the throttle butterfly to make sure that it is fully shut at idle? Is the acceraltor cable badly adjusted and hodling it open.

It will be something like this. You will just have to keep looking until you find it...