I was a FORD tech for seven years in a very large dealership. It was during the FE engine's primetime (64-71).

We contacted cemented the intake gaskets to the heads. And contact cemented the end corks to the ends of the block. We then used "a finger" worth of sealer just in the four corners where the intake gaskets meet the end corks. The manifold went on dry. Make sure the contact cement is dry on both surfaces before you stick it together, "too soon" and it will not hold.
The end corks are thick, more than I would want to use silicone to seal. Silicone works great, but not to fill a quarter of an inch IMO.

We also "always" used a new bypass hose and mounted the manifold without the hose clamps to make the hose easy to flex up while mounting the manifold on a engine that already had the water pump mounted. We put the hose clamps on after the mainfold. It's also a much easier job to use two people to install the manifold, one on each side. A large vise grip clipped in the middle on each side makes a good hand hold.