For 49 years, Fidel Castro has shouted to the world: Cuba Si, Yankee No. In February, though, the seeds for dramatic change were planted, when the ailing Cuban dictator called it quits — a departure that some Wall Street pros say could lay the groundwork for a boon for investors.

Adding credence to the idea that America-Cuba relations will change for the better is a recent statement by Senator Obama that if he wins the White House, he would be amenable to one-on-one talks with Raul Castro, who has taken Cuba’s presidential reins.

Envisioning a renewed America-Cuba relationship, some investors are already hopping aboard the Cuban investment bandwagon, as exemplified by a sharp run-up in the Herzfeld Caribbean Basin Fund, which invests in companies doing business in the region, following Fidel Castro’s resignation.

Another sign Wall Street is ready to say “si” to Cuba is some pent-up interest in Carnival Corp. ($39.34), the world’s biggest cruise ship company. Based in Miami, it operates throughout the Caribbean and is viewed as a significant beneficiary of Fidel Castro’s farewell. Some of Carnival’s institutional holders are even said to have fattened their positions somewhat, partly because of the political change.

No one, of course, expects America and Cuba to become bosom buddies overnight, but one enthusiast, the Complete Investor, a New York newsletter, is telling subscribers it’s not too soon to think about the benefits of a resumption of economic contacts. Noting that the reign of 76-year-old Raul Castro is likely to be short-lived, one of the letter’s analysts, Nick Lanyi, raises the prospect, which some political figures view as a near certainty, of the two countries eventually resuming ties.

As a result of a 1963 U.S.-imposed embargo, it’s currently illegal for American citizens to do business with Cuba, aside from some agricultural and medical transactions. If restrictions were eased or lifted, many American companies would no doubt be eager to do business with a nation of 11 million people just 90 miles south of Florida, Mr. Lanyi notes.

Carnival is in a prime position to capitalize on falling barriers between the two countries, and would likely grab a huge chunk of the cruise traffic.

In recent years, Carnival has enjoyed robust demand for cruise ship berths, spurred by America’s growing retiree numbers and many upper-middle-class baby boomers, the industry’s most productive demographic groups. Europe and Japan are also providing an expanding pool of likely customers in these age categories.

Carnival, clearly on a fast track, saw revenues increase to $13 billion last year from $9.7 billion in 2004, while net income sprinted an average 20% a year over the past five years.

In addition, Carnival is strong financially, has a solid cash flow that supports $3 billion or more in annual capital spending, and offers a nearly 4% dividend yield.

On the negative side, a slowing economy and sharply rising fuel prices have been a drag on growth recently, and fourth-quarter results were disappointing. But analysts look for rising sales and earnings this year, as the company continues to expand capacity (an additional 22 ships are on order for delivery through 2012).

With the stock trading at around 13.5 times estimated 2008 earnings, Mr. Lanyi rates it “a bargain for long-term investors” and has a price target of $55, roughly a 38% gain from current levels.

Another beneficiary of resuming ties with Cuba would be Copa Holdings SA ($34.49), an airline in Latin America and the Caribbean that is nearly 50% owned by Continental Airlines. Based in Panama, it operates a network of flights to 36 cities in 21 countries throughout the region. A low-cost carrier, its operating margins are among the highest in the industry and interest on debt is amply covered by cash flows.

Earnings may remain flat this quarter and next because of higher fuel costs, but they should pick up, Mr. Lanyi says, if oil prices come back to earth and the Latin American economy continues to grow. The stock trades at about 9.3 times projected 2008 earnings.

In the film “The Godfather Part II,” the head of a Mafia crime family, Michael Corleone, refuses to invest in Cuba because of political upheaval in the country. He was right then, but given the real-life political upheaval there, a number of Wall Street pros say it’s now time to rethink the issue, say “si” to Cuba, and make a decent buck doing so.

dandordan@aol.com