* S&P 500 closed at record Thursday, on track for strong Feb
* Fourth-quarter GDP data on tap, seen rising 2.5 pct
* Salesforce.com raises revenue outlook, shares up
* Futures down: Dow 24 pts, S&P 3.7 pts, Nasdaq 5 pts
By Ryan Vlastelica
NEW YORK, Feb 28 (Reuters) - U.S. stock index futures dipped on Friday, with investors reluctant to make big bets after the S&P 500 closed at a record and ahead of closely watched data on economic growth.
* The benchmark index closed barely in positive territory for the year on Thursday, ending at a record above a level that has served as resistance this week. All three major indexes are set to end February and the week with gains, and the Nasdaq is on track for its fourth straight weekly rise.
* A preliminary estimate on fourth-quarter gross domestic product, due at 8:30 a.m. EST (1330 GMT), is expected to show growth of 2.5 percent. Market participants will look for signs of whether a severe winter hurt growth in the quarter.
* Recent indicators have come in below forecasts, with many analysts pinning that to bad weather rather than worsening fundamentals. Stocks rose on Thursday after Federal Reserve Chair Janet Yellen indicated support for this theory.
* The February Chicago Purchasing Managers Index is also on tap, as is the final February reading on consumer sentiment from the Thomson Reuters/University of Michigan Surveys of Consumers. The PMI report, due at 9:45 a.m. EST, is seen falling to 57 from 59.6 last month, while sentiment is expected to be flat.
* S&P 500 futures fell 3.7 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 24 points and Nasdaq 100 futures lost 5 points.
* For the month, the Dow is up 3.7 percent, the S&P is up 4 percent and the Nasdaq is up 5.2 percent. For the week, the Dow is up 1.1 percent, the S&P is up 1 percent and the Nasdaq is up 1.3 percent.
* Salesforce.com Inc late Thursday raised its full-year revenue forecast and said it was looking to improve its adjusted operating margin. Shares rose 1 percent to $66.88 before the bell.
* Gap Inc late Thursday reported earnings that beat expectations, though the apparel retailer said it expected unfavorable currency exchange rates will hit its full-year profit.
* Jos. A. Bank Clothiers Inc late Thursday rejected Men's Wearhouse Inc's revised takeover offer, calling it inadequate, though it was willing to talk about a higher bid.
* Toy maker Mattel Inc agreed to buy Canada's Mega Brands Inc for about $460 million.
* In her testimony before the Senate Banking Committee, Yellen said it would take a "significant change" to the economy's prospects for the central bank to put plans to reduce its bond-buying program on hold.
* On Friday, Dallas Federal Reserve Bank President Richard Fisher said the central bank should halt its stimulus as soon as circumstances make it possible.