A win for Everton would be absolutely massive for their hopes of qualifying for Europe.
If they won at Palace they would be level on points with Brentford (51) with two games to go.
Bournemouth (55) and Brighton (53) would be within touching distance but Everton will likely have to beat Palace and then win their final two games at home to Sunderland and away at Spurs on the final day to have any chance of finishing above those two.
European spots are likely to go down to seventh place in the Premier League and if Aston Villa win the Europa League and finish in fifth place in the league, the team who finishes in sixth place in the Premier League would qualify for the Champions League next season.
So, yeah, Everton winning at Palace is huge as they could potentially still qualify for the UEFA Champions League next season. But more than likely Europa League or Conference League is well within reach.