Donald Trump’s big New York win killed off yet another nugget of conventional wisdom in this topsy-turvy campaign: he grabbed an outright majority of Republican primary voters for the first time.

And polling data ahead of Tuesday’s five “Acela primaries” indicates that his home-state performance was no fluke.

Pundits long argued that Trump’s appeal would stay limited to a core constituency of 30 to 35 percent of primary voters.

His favorability ratings fueled the assumption. One recent poll found that 69 percent of Americans — and close to half of all Republicans — view the GOP front-runner unfavorably.

That “low ceiling” should have left Trump vulnerable to challengers once the crowded field of candidates winnowed down. But that’s no longer the narrative in a political season that’s rewriting the rulebook.

If there’s still a ceiling in this race, it must be a vaulted one.

Trump’s 60 percent victory in the Empire State sets the stage for a fresh surge of big wins. He is expected to dominate in all of the primaries being held Tuesday, in which 172 delegates are up for grabs.

The latest polls in Connecticut show him flirting with 50 percent there, with support for opponents Ted Cruz and John Kasich evenly split. A Delaware poll points to a dominant 55 percent win for him there, with vote totals above 40 percent likely for Trump in Pennsylvania, Maryland, and Rhode Island.

New York is no bellwether for the GOP — it votes reliably for Democrats in presidential elections, and its Republican Party generally goes against the conservative grain.

Still, Trump outperformed poll predictions here by about 10 percent and picked up 89 delegates to Kasich’s four, a result that demoralized “NeverTrump” Republicans who oppose his nomination.

Cruz’s third-place, zero-delegate tally in New York makes it harder for him to campaign on the claim that he’s the only plausible alternative to the bombastic billionaire — although that didn’t stop him from doing so on Saturday.

“Donald Trump is a Washington insider who has been supporting liberal Democratic politicians for 40 years,” Cruz told 1,000 supporters at a rally in Monroeville, Pa.

“He says you’ve got to learn to cut deals with the Democrats, go along to get along,” Cruz argued. “I have to give Donald credit — he’s betraying us before he even got elected.”

A day after Trump’s chief adviser, Paul Manafort, promised Republican officials that the candidate plans to rein in his inflammatory rhetoric ahead of the general election, Trump said Saturday that he’s “not toning it down.”

“Isn’t it nice that I’m not one of those teleprompter guys?” Trump asked a crowd of 3,000 in Watertown, Conn.

Republicans looking to derail the Trump train are pinning their hopes on Indiana, which votes May 3 and seems tailor-made for his opponents. Its demographics mirror those of Wisconsin, where Cruz notched a major win, and its voters know Kasich, the former governor of neighboring Ohio.

But Indiana’s first two pre-primary polls, released Friday, show Trump beating them both. Polling averages put him at 39 percent of the vote there, to Cruz’s 32 percent and Kasich’s 19 percent.