But why on earth would you WANT to plug them all up?
Whilst you might get away with doing some of them, there are others that you DEFINATELY don't want to plug up. The vacuum line between the intake manifold and the brake cylinder for example - plug this and you'll lose all power assistance on your brakes. Which isn't all that good really...
If you did plug them all, I doubt the engine would explode or have any lasting damage, but I'm pretty sure that it would run pretty rough or something