The RCA Corp. has begun negotiations to acquire C.I.T. Financial Corp. for more than $1 billion. If successful, the acquisition would be one of the largest in the history of the nation.

RCA President Edger H. Griffiths has mentioned financial service enterprises as possible acquisition targets for RCA. Griffiths also targeted electronics companies and savings and loan associations for possible acquisition.

"We're in a strong financial position," he told the Wall Street Journal earlier this year. "We could use cash and stock. What we get for Alascom (RCA Alaska Communication Inc.) isn't any practical limitation on what we can do."

Griffiths was referring to the sale for $200 million in cash of the Alaska subsidiary to Pacific Power and Light Co. The sale occurred on June 1 of this year. The money from that sale, together with the $240 million in cash and short-term assets on hand at the end of 1978, provided RCA with a strong base from which to look for new acquisitions.

The announcement on Tuesday by C.I.T. and been approached by "a major U.S. corporation" the previous day sent its stock soaring 9-3/8 points to close at 49 3/4 at the end of the day.

Trading of C.I.T. stock was suspended this morning. It opened at 51 1/2 shortly after noon and closed at 53 1/4 in heavy trading. RCA stock was unchanged at 24 3/4.

Neither corporation would comment today on the proposed acquisition other than a joint statement that "no agreement has been reached and there is no assurance that any agreement will be reached."

"They are great cash generators, the finance companies, and they can provide permanent funds for any development," he continued. "I'm sure that RCA can benefit from it.

Among financial service concerns, C.I.T. in particular is cash rich, having sold its bank subsidiary, The National Bank of North America, to the National Westminster Bank Ltd. of London in April for about $425 million.

"C.I.T. would create a bigger cushion of earnings against which the cyclical electronics earnings can operate," said John J. Arscott, who follows RCA for Brown Brothers Harriman. "It's still too early to tell, but it could certainly stabilize the earnings patterns.

"It's a pretty good deal for the C.I.T. stockholders," he continued. "C.I.T. was selling in the 30s in the beginning of the year, and RCA is paying in the 60s for it. That makes me a little queasy. It's an acquisition of an average company for above the Wall Street market willingness to pay and above the stated book value."

According to a story in today's Wall Street Journal, the share price under discussion ranges from $60 to $67 billion could change hands for over 20 million shares of C.I.T. stock if the sale is consumated.

There is some feeling on Wall Street that the offer made last week by the Midland Bank Ltd. of London to acquire Walter E. Heller International, another financial service business, at nearly twice its $24 a share book value put C.I.T. in a strong bargaining position with RCA.

If completed, the C.I.T. acquisition would overshadow the well-publicized problems that RCA has been having with the National Broadcasting Co., for years the leading money-maker among its subsidiaries.

Last year, for the first time, NBC lost that distinction to another RCA subsidiary, the Hertz Corp., the largest car rental company in the nation. Griffins hired Fred Silverman last June from ABC television to run NBC in an effort to regain its position of prominence.

"I suppose this could deflect attention from that for a while," Arscott said. "But this could also give RCA the image of a conglomerate, which is not as attractive as that of a solid electronics company." CAPTION: Picture, EDGAR GRIFFITHS . . . possible takeover targets