GenTek Inc, a U.S. maker of specialty chemicals and engine components, said on Monday it has agreed to a takeover by a unit of private equity firm American Securities for $411 million.

Its shares rose 40 percent in premarket trading to their highest level since early 2007 on the news.

The American Securities LLC subsidiary will assume about $262 million in debt.

Under terms of the deal, ASP GT Acquisition, a subsidiary of American Securities, will pay $38 per GenTek share, a 41 percent premium over Friday's closing price of $27 on the Nasdaq.

We believe that the transaction will have a positive outcome for our customers and employees, said William Redmond, chief executive of the Parsippany, New Jersey-based company.

In premarket trading on Monday, the shares rose to $37.75.

As of Friday's close, GenTek stock was up 79 percent year to date, more than double the 33 percent rise of the Nasdaq composite index .IXIC.

(Reporting by Scott Malone in Boston and Nick Zieminski in New York; Editing by Derek Caney and Maureen Bavdek)

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