Despite a second medal of the Games, Wiffen admitted he had “a lot higher aspirations” for the 1500m final.
“To be honest, the 800m surprised me at the start of the week,” he told BBC Sport.
“Coming into this race I was ready. I completely was in the right shape to go a lot faster than the world record but that’s just swimming – some days you have it, some days you don’t.
“If you’d told me I’d get a bronze medal at the start of the week, I’d be over the moon. Now I’m coming away with gold and a bronze, it’s kind of special.”
After a cool and calm entrance into the arena, which had already reached fever-pitch with two French swimmers also in the final, Wiffen settled into the race in fourth position as Finke looked to break away from the rest of the field.
After qualifying for the final third fastest, some five seconds behind Wiffen’s quickest time of 14:40.34, the 24-year-old American turned the script on its head on Sunday’s final.
Paltrinieri was the first swimmer to try to go with Finke, as Wiffen swam his own race in third. He tried to catch the leading pair at the race’s midpoint but was unable to match the pace and had to settle for a comfortable third.
“To be honest, sometimes after a great 800m, it’s not a great 1500,” Wiffen added.
“Both those times in the 800m and 1500m were very good. That was my fourth fastest time ever [in the 1500m] so I’m still pleased with it.
“We’ll come better next season and go under that WR [world record].”