The Merrimac was of 3000 tons against 1255 of the Monitor. She also carried 363 men and officers against 42 of the little Monitor, while the armaments were four heavy rifled English guns and six IX-inch Dahlgrens of the former against two XI-inch Dahlgrens of the Monitor.
The Virginia didn't have "four heavy rifled English guns" on her. She had a 7" Brooke rifle at the bow and stern, and a 6.4" Brooke rifle on each broadside.
But it was an interesting read, if a bit biased to the north on the Monitor and Merrimac section.