I have, what I think, is a '57 intake manifold, casting number ECZ-9425-B. Date code (I think) 73-T.  I understand that a heat crossover tube extends from a choke attachment point on the passenger side exhaust crossover position, under the carb, to the driver side exhaust crossover position (where the air is taken into the tube).   
I cannot find any hole on the driver's side of the manifold.  What am I not understanding?  The tube is replaced by driving it out from one side to the other, for which the manifold has to be removed.   
I will try to post some pictures from another device.  
Thanks, Ralph