Having already secured one gold and three bronze medals during the regatta in South Korea, the eights crew finished ahead of Germany and the United States.
The men's eight were bronze medal winners at the London 2012 Olympics, where Germany took the gold.
But it was a momentous victory on Tangeum Lake on Saturday for the British crew - Daniel Ritchie, Tom Ransley, Alex Gregory, Pete Reed, Mohamed Sbihi, Andrew Triggs Hodge, George Nash, William Satch and cox Phelan Hill.
They dictated the pace of the 2000m race, leading at all of the checkpoints.
On the final day of competition the men's lightweight four managed to secure third, with Adam Freeman-Pask, Jonathan Cleggwon, Chris Bartley and William Fletcher taking bronze.
More top news
Philippa has the weekend weather for the east
Philippa has the weekend weather for the west
A spate of car thefts at motorway services in Berkshire are believed to be linked to technology that stops them remotely locking.