Fiery Kenneth Langone, the combative, embattled 69-year-old billionaire investor and a founder of Home Depot, is about to turn up the heat in his battle with the New York Stock Exchange in an effort to derail the Big Board’s proposed acquisition of Archipelago Holdings, the Chicago-based electronic trading firm.

I’ve learned – no ifs, ands, or buts – that Mr. Langone, who, as widely reported, is planning a competing offer, is likely to go public next week with his case for opposing the NYSE-Archipelago deal, and, as part of a group effort, accompany it with roughly a $4 billion to $4.5 billion bid for the exchange.

That’s the value Mr. Langone, an ex-NYSE director, is reliably said to place on the exchange, based on, among other things, its valuable real estate holdings, its $1 billion of cash in the bank, a great brand name, as prestigious, he’s said to believe, as that of Coca-Cola, and a fine information system. “The New York Stock Exchange is just worth a hell of a lot more than the current Big Board offer,” he’s telling friends and supporters.

At the moment, though, to confirm that view, a group headed by Mr. Langone is doing a thorough analysis of the Big Board to make certain the values are indeed there to warrant a $4 billion to $4.5 billion offer. So far, I’m told, the numbers look quite good. If indeed the analysis bears out Mr. Langone’s belief, an offer will be made next week.

Under the contemplated Big Board-Archipelago deal, the NYSE’s 1,366 seat holders will receive $400 million in cash and 70% of the shares, while Archipelago shareholders will retain 30% of the combined company. Based on the latest price of a Big Board seat – the last one sold Monday at $2.4 million – the NYSE, on its own, is valued at about $3.3 billion. Factor in Archipelago and the exchange offer is worth slightly over $4 billion. Archipelago shares (symbol is AX) closed yesterday at $33.54.

However, it’s believed there is a good deal of air in Archipelago’s shares since they were trading at under $20 when the deal with the NYSE was announced April 21.

Much of Mr. Langone’s ire is directed at investment banker Goldman Sachs, an adviser to both the NYSE and Archipelago in the proposed merger transaction, which holds seats on the exchange and has a 15% stake in the electronic trading platform. He is said to believe the fact that Goldman represents both sides in the transaction is a conflict of interest, an argument that Goldman rejects.

Top brass at Goldman suggest that Mr. Langone’s talk of a Big Board offer is laughable, that he’s more noise than substance, that he will never muster the required financial support to make the necessary multibillion-dollar bid and will soon disappear, if he hasn’t already done so, with his tail between his legs.

Asked about the possibility that a roughly $4 billion to $4.5 billion bid for the NYSE might be on the way from his camp and possibly as early as next week, Mr. Langone, a strong booster of former ousted Big Board chief Richard Grasso, declined comment. When I persisted, he told me “I will not address that issue.”

One of Mr. Langone’s allies tells me he has said that raising the needed funds to make an enticing bid that could win over Big Board seat holders is “a slam dunk.” He added that Mr. Langone is said to also believe the Big Board offer represents the “absolute minimum,” and will surely run afoul of growing opposition from NYSE seat holders.

What may not be a slam dunk, though, are the hurdles he’ll have to overcome to achieve his goal. For starters, he requires the approval of the Securities and Exchange Commission, plus two-thirds of the exchange’s 1,366 seat holders. Also, Mr. Langone has been sued by New York Attorney General Eliot Spitzer for his role in Mr. Grasso’s controversial $139 million pay package (Mr. Langone, in a previous interview, told me it was only a matter of time before Mr. Spitzer abandoned that case).

Many Wall Street pros I talk to think it likely that the NYSE-Archipelago deal will go through, given Goldman’s Wall Street clout. But one of Mr. Langone’s boosters tells me the Street has to be loco to sell him short. He, in fact, likens him to Samson of Samson & Delilah fame. “You’ll recall,” he said, “that Samson, blind, his hair cut short and his strength sapped, managed to pull down two pillars of a Roman temple, in the process killing thousands of his enemies. Mr. Langone,” he added, “is not blind, but bald and a pretty strong fella.”