Federal prosecutors proved Vincent “The Chin” Gigante’s son is a chip off the old block – and now he’s headed to a cellblock.

Andrew Gigante, the high-rolling son of the notorious, crazy-acting Mafia boss, was sentenced to two years in prison for racketeering and extortion yesterday – and ordered to fork over $2 million in criminal proceeds.

Gigante, 46, previously pleaded guilty to using his Genovese crime family ties to seize control of the International Longshoremen’s Association in New Jersey, New York and Miami.

He denied using violence to impose his will on the union, but prosecutors say his victims feared Gigante would use mob muscle to influence them.

There was “an implicit threat of harm, that if moneys were not paid to the Genovese family, and that included [mob] associate Andrew Gigante, it would lead to . . . violence,” Assistant U.S. Attorney Paul Weinstein told Brooklyn federal Judge Leo Glasser.

The feds busted Vincent Gigante and his son in a massive roundup, aimed at loosening the Mafia’s grip on the waterfront.

For decades, “the Chin,” the Genovese crime family boss, tried to thwart investigators with a mumbling and stumbling “Oddfather” routine, and delayed trials with regular trips to the mental-health ward.

His habit of wandering around Greenwich Village dressed in his bathrobe earned him a prominent place in mob history – but prosecutors never bought the act.

In April, the 75-year-old mob big made the stunning admission it was all a ruse, and pleaded guilty to faking mental illness.

Already in prison, serving a 12-year sentence on racketeering charges, he plea-bargained an additional three years behind bars.

The younger Gigante, who for years carried messages between his jailed father and the Genovese family, pleaded guilty the same day.

At the time of his arrest in January 2002, Andrew Gigante earned $350,000 per year as an executive with Newark-based Bay Container and Portwide Cargo Securing.

Initially, defense lawyer Gustave Newman portrayed him as a “pillar” of his Norwood, N.J., community – and submitted complimentary letters from the local mayor and police chief. As the result of his guilty plea to extortion charges, he is permanently barred from doing business on the waterfront.

Yesterday, Newman asked that Gigante be allowed to serve his time in Otisville, N.Y., a low-security facility about 90 minutes from the city.