Katie Beluch and Sydney Jackson scored twice each in the first half, and Eastern cruised to a five-goal halftime lead.
McGroarty is in his 22d season. He surpassed former Cherry Hill East coach Lee Troutman's 316 wins.
He said he's been lucky to be in the right place and said Delsea, his first coaching job, and Eastern are great programs.
In other Olympic Conference action:
Courtney Simpson made 11 saves for Cherokee, and Brianna Davis recorded nine for visiting Shawnee as the teams played to a scoreless tie.
Rachelle Ross scored twice, and Bridge McVeight recorded the four-save shutout in Lenape's 3-0 win at Washington Township.
Gianna Morrone's first-half goal proved to be enough as Bishop Eustace blanked visiting Seneca, 1-0.
Burlington County. Erica Bruno scored in the first half, and Florence held on to edge host Burlington City, 1-0.
Tri-County. Megan Morrison scored twice, and Alyssa Whipkey recorded 10 saves as Pennsville downed visiting Penns Grove, 6-1.
Lauren Crudele scored three times, and Eileen Dzwill added two goals and two assists to help host Bishop Eustace past Seneca, 8-1, in an Olympic National game.
In other Olympic action:
Caroline Haeffner scored twice and Breck Urban had two assists as Paul VI cruised past visiting Timber Creek, 3-1.
Austyn Cuneo recorded four goals, and Jade Dixon chipped in with three more as Eastern rolled past visiting Cherry Hill East, 12-0.