Sunderland were in the old Second Division when they stunned favourites and cup holders Leeds at Wembley in 1973, with the late Ian Porterfield scoring the only goal.
As a boyhood Black Cats fan, O'Neill is well aware of the significance of that victory in the club's history and would love to mark the 40th anniversary in fitting style.
"We have to make a couple changes in the team but it wouldn't be a case of making them for the sake of it," O'Neill said ahead of Saturday's third-round tie at Bolton.
"It's a competition we would like to do well in; we got to the quarter-finals last year, which is as good a run as we have had in a few years.
"It is important for the fans and the football club and while we accept that in recent times the Premier League has been the be-all and end-all, it should not detract away from it.
"I consider it a fantastic competition and there's untold advantages of trying to stay in the competition.
"I went to watch Bolton on Tuesday and I thought they played very well against Leeds (in a 1-0 defeat at Elland Road) and they will go into the game with very little to lose and play with some sort of freedom. We have to try and guard against that.
"It's the 40-year anniversary of our great triumph at Wembley and for that reason alone it's worth our while to try and stay in the competition as it's still a great competition."
Sunderland climbed away from the relegation zone with three wins in four games in December, but travel to the Reebok Stadium on the back of two straight defeats.
O'Neill felt the second of those - a 3-0 loss to Liverpool at Anfield on Wednesday - was "a game too far" for his small squad and would like to bring in new faces during the January transfer window.
"We obviously would like to do something if we can because we have the smallest squad in the Premier League and we want to do something about that between now and the end of January," O'Neill added in his pre-match press conference.
"But then any other club would say the same thing, we want to improve the club if we can.
"It is difficult as it's the only three or four-week period you get to improve your squad.
"A lot of clubs are chasing the same thing, not necessarily the same player, but the same ideal."