McDermott, who scored 55 in game one, posted his maiden ODI century in just his fourth appearance with a classy 104 off 108 balls on Thursday.
Head, who was the matchwinner on Tuesday with 101 off 72 balls, fell just short of posting consecutive centuries when he was dismissed for 89 off 70 balls.
Marnus Labuschagne (59 off 49 balls) and Marcus Stoinis (49 off 33 balls) also joined in on the fun to put Australia in the box seat to take an unassailable 2-0 lead in the three-match series.
McDermott's century at Gaddafi Stadium in Lahore came 32 years after his father Craig McDermott snared 5-44 at the same ground to inspire Australia to an 18-run victory over Pakistan.
"It's lovely to get the first (century), and an absolute privilege to do it out there with a good mate in Marnus as well," Ben McDermott told the host broadcaster.
The innings started off badly for Australia after skipper Aaron Finch missed a full toss and was trapped lbw by Shaheen Afridi (4-63) for a first-ball duck.
Afridi was fired up early, and he was filthy at the end of the fifth over when he was struck down the ground for four by McDermott.
After exchanging words with McDermott, Afridi walked into the path of Head with the intent of bumping into him.
Head turned his body at the last moment to avoid impact, and the incident only served to further motivate the Australian pair.
McDermott took 12 balls to get off the mark, but he unleashed after that to finish with 10 fours and four sixes.
Head was in scintillating touch from the outset, cracking six fours and five sixes in his blistering knock.
Their departures didn't noticeably slow the run rate, with Labuschagne and Stoinis keeping the runs flowing.
McDermott, Head and Labuschagne were considered fringe ODI players before the current series, but their form will help boost their chances of becoming regulars leading into the 2023 50-over World Cup.
Their performances further showcased Australia's depth on a white-ball tour in which star batters David Warner (rested) and Steve Smith (elbow) are missing.
Mitch Marsh (hip), Josh Inglis (COVID) and Ashton Agar (COVID) are also grounded, while MItchell Starc, Pat Cummins, and Josh Hazlewood have been rested from the white-ball games.