Which 273?

I have a 66 Barracuda Formula S that was delivered 10-12-1965 according to the certicard. My question is do I have the 65 and earlier engine with the unique intake/ head angle bolts or the later. I would like to use a newer dual plane intake. Driver side casting # 2465330-4. Passenger side 3-17-65. See pics, please let me know what you think.046.JPG 048.JPG 050.JPG