Good question, JB. Yes, the 55-56 heads are supposed to have a lot better intake port.
These are aftermarket heads from Hot Heads Research and Racing. This is what they say about them on their website:
"The best heads ever made for the early Chrysler Hemi, period. We started with a clean slate when we CAD-designed these water-jacketed aluminum heads for '51 - '59 Chrysler 331, 354, and 392 blocks. Using the latest in casting technology, our heads are cast from 356-T6 aluminum, with an extra thick 5/8 inch deck and combustion chamber, all with machining operations done on a CNC machine. We started with the favorable 1955 factory raised intake port design, improved it, and added a better-flowing rectangular exhaust port to increase flow. Hardened seats are installed for use with unleaded fuel, with intakes at 2.0625 (2 1/16) and exhausts at 1.80 inch, with bronze guides installed for 11/32 inch valve stems. We enlarged the pushrod holes to allow for larger diameter pushrods, and machined the spark plug tube seals into the head, and eliminated the heat riser to the intake manifold. Heads are 100 percent leak tested for quality control."

So far, I'm very happy with them except for the leak. But that is always a risk when you port.