To quote Sean Wilentz (of The Rise of American Democracy fame): "If a mere 9,000 votes in New York, Ohio, and Kentucky had shifted from one column to the other, and if New York, with an Adams majority, had followed the winner take all rules of most other states, Adams would have won a convincing 149 to 111* victory in the Electoral College."
After some checking, his calculations were wrong numerically, but still true. Adams had 83 Votes OTL, +20 from a winner take all NY (have some better 1827 state elections as your POD), +16 from Ohio, +14 from Kentucky. Adams now has 133 Votes to Jackson's 128, just barely past the 131 marker. So long as there are no faithless electors, Adams in is the clear.