NEW YORK - The basic money supply dropped a record $5.4 billion in the latest statement week, the Federal Reserve Board reported yesterday in what could signal the first significant break this year in the surge of money growth that many analysts say has contributed to the high rate of inflation.

The drop, if sustained, however, could also portend much slower economic growth and possibly a recession in early 1979 as credit availability begins drying up for housing, consumers and businesses seeking credit.

"It may be that the sustained period of tightening which began last April is finally showing up in a slowing of monetary growth," said David Jones, an analyst with Aubrey G. Lanston & Co. He noted that the lag between higher interest rates and curtailed money supply growth is often six months or more.

But if the money supply in contracing now in reaction to moves last April - when the Fed first began cranking up short-term interest rates - the impact could be even sharper next spring as a result of the drastic Fed tightening moves that have taken place in the past few days to defend the dollar. These have sent short-term interest rates up nearly one percentage point in the last week.

The Fed yesterday continued to aggressively raise the level of the federal funds rate, with a new larget of 9 7/8 percent that analysts say could be just a way-station to 10 percent. A week ago this key rate which the Fed used to control demand for credit stood at under 9 percent.

A 10 percent federal funds rate imphes at least an 11.5 percent commercial bank prime rate, analysts said, but it may take some weeks before the banks work up to this level. The prime was just raised to 105 percent this week.

When we get to the spring of next year, we could see close to zero growth in economic activity," Jones said.

While the basic money supply or M-1, which includes cash and checking account deposits, dropped $5.4 billion to $358.9 billion, the broader money supply known as M-2, which also includes savings deposits, dropped $3.6 billion to $865.7 billion in the latest week.