As President Carter's intended for the chairmanship of the Federal Reserve Board, Paul Volcker, 51, knows it is a wise nominee who promises to keep his head down and the prime rate up. Courting confirmation before the amiable Senate Banking Committee, the cigar-smoking Volcker listed as credits his experience in the Kennedy, Johnson and Nixon administrations and the respect of hard-nosed French and German leaders. As a debit, there was Volcker's architecture (in 1971) of the floating-exchange-rate system, under which the dollar has lately suffered a trashing. Volcker, who gave up the presidency of New York's Federal Reserve Bank, will take a patriotic $53,000 salary cut to become $57,000-a-year Fed chairman. He may also want to change smokes. Nixon's chairman, Arthur Burns, puffed a pipe—and lasted eight years. Carter appointee G. William Miller, a nonsmoker, was promoted to Treasury Secretary. Cigars are an idea whose time may have passed. The Administration's best-known puffer of panatelas was Mike Blumenthal, whose Treasury job was snubbed out in last month's Cabinet purge.