James also pulled down eight rebounds as the defending champions sealed a 4-3 series win and a date with the San Antonio Spurs in the Finals.
"By any means necessary ... we took care of business," James said shortly after Monday's win.
Roy Hibbert scored 18 points for the Pacers, who edged the first quarter but fell apart under the weight of a 33-point second from the Heat.
Pacers star Paul George was held to seven points on 2-for-9 shooting and fouled out in the final period.
"The great thing is we're a young team and we are past the building stage," George said.
"This is really our first year tasting success. The rate we are going, we see championships soon."
In contrast, Dwayne Wade answered his critics by matching his post-season high of 21 points and nine boards to help Miami go up by as much as 28 points on their way to the blowout win.
"You never want to take anything for granted," Wade said.
"Being here three straight years in a row, going back to the finals, is an amazing feat. I'm just glad we were able to do it.
"Everything that happened in the first six games didn't mean anything to us. It was about tonight. It was about Game 7. It was about finding a way to win here at home."
Game 1 of the 2013 NBA Finals will be in Miami on Thursday.