The biggest 3-day debut for Quentin Tarantino film, not counting for inflation, belongs to Inglorious Basterds, which opened to $38 million in August 2009 on its way to $321.4 million worldwide. Django Unchained also had a successful opening, earning $63.4 million over six days in advance of a $425.4 million worldwide total, but since it opened on Christmas Tuesday in 2012, it isn’t a 1 to 1 comparison.
Article source: https://www.cinemablend.com/news/2474311/how-much-money-once-upon-a-time-in-hollywood-could-make-in-its-opening-weekend